ASTM B-733-97 金属表面化学镀镍磷层规范标准
Designation:B733–97
Standard Speci?cation for
Autocatalytic(Electroless)Nickel-Phosphorus Coatings on Metal1
This standard is issued under the?xed designation B733;the number immediately following the designation indicates the year of original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(e)indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1.Scope
1.1This speci?cation covers requirements for autocatalytic (electroless)nickel-phosphorus coatings applied from aqueous solutions to metallic products for engineering(functional)uses.
1.2The coatings are alloys of nickel and phosphorus pro-duced by autocatalytic chemical reduction with hypophosphite. Because the deposited nickel alloy is a catalyst for the reaction, the process is self-sustaining.The chemical and physical properties of the deposit vary primarily with its phosphorus content and subsequent heat treatment.The chemical makeup of the plating solution and the use of the solution can affect the porosity and corrosion resistance of the deposit.For more details,see ASTM STP265(1)2and Refs(2)(3)(4)and(5) also refer to Figs.X1.1,Figs.X1.2,and Figs.X1.3in the Appendix of Guide B656.
1.3The coatings are generally deposited from acidic solu-tions operating at elevated temperatures.
1.4The process produces coatings of uniform thickness on irregularly shaped parts,provided the plating solution circu-lates freely over their surfaces.
1.5The coatings have multifunctional properties,such as hardness,heat hardenability,abrasion,wear and corrosion resistance,magnetics,electrical conductivity provide diffusion barrier,and solderability.They are also used for the salvage of worn or mismachined parts.
1.6The low phosphorus(2to4%P)coatings are microc-rystalline and possess high as-plated hardness(620to750HK 100).These coatings are used in applications requiring abra-sion and wear resistance.
1.7Lower phosphorus deposits in the range between1and 3%phosphorus are also microcrystalline.These coatings are used in electronic applications providing solderability,bond-ability,increased electrical conductivity,and resistance to strong alkali solutions.
1.8The medium phosphorous coatings(5to9%P)are most widely used to meet the general purpose requirements of wear and corrosion resistance.
1.9The high phosphorous(more than10%P)coatings have superior salt-spray and acid resistance in a wide range of applications.They are used on beryllium and titanium parts for low stress properties.Coatings with phosphorus contents greater than11.2%P are not considered to be ferromagnetic.
1.10The values stated in SI units are to be regarded as standard.
1.11The following precautionary statement pertains only to the test method portion,Section9,of this speci?cation.This standard does not purport to address all of the safety concerns, if any,associated with its use.It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limita-tions prior to use.
2.Referenced Documents
2.1ASTM Standards:
B368Test Method for Copper-Accelerated Acetic Acid-Salt Spray(Fog)Testing(CASS Testing)3
B374Terminology Relating to Electroplating3
B380Test Method of Corrosion by the Corrodkote Proce-dure3
B487Test Method for Measurement of Metal and Oxide Coating Thicknesses by Microscopical Examination of a Cross Section3
B499Test Method for Measurement of Coating Thick-nesses by the Magnetic Method:Nonmagnetic Coatings on Magnetic Basis Metals3
B504Test Method for Measurement of Thickness of Me-tallic Coatings by the Coulometric Method3
B537Practice for Rating of Electroplated Panels Subjected to Atmospheric Exposure3
B567Method for Measurement of Coating Thickness by the Beta Backscatter Method3
B568Method for Measurement of Coating Thickness by X-Ray Spectrometry3
1This speci?cation is under the jurisdiction of ASTM Committee B-08on Metal
Powders and Metal Powder Products and is the direct responsibility of Subcom-
mittee B08.08.01on Engineering Coatings.
Current edition approved July10,1997.Published October1997.Originally
published as B733–https://www.wendangku.net/doc/2510644734.html,st previous edition B733–90(1994).
2The boldface numbers given in parentheses refer to a list of references at the
end of the text.3Annual Book of ASTM Standards,V ol02.05.
1
Copyright?ASTM International,100Barr Harbor Drive,PO Box C700,West Conshohocken,PA19428-2959,United States.
B571Test Methods for Adhesion of Metallic Coatings3
B578Test Method for Microhardness of Electroplated Coatings3
B602Test Method for Attribute Sampling of Metallic and Inorganic Coating3
B656Guide for Autocatalytic Nickel-Phosphorus Deposi-tion on Metals for Engineering Use3
B667Practice for Construction and Use of a Probe for Measuring Electrical Contact Resistance4
B678Test Method for Solderability of Metallic-Coated Products3
B697Guide for Selection of Sampling Plans for Inspection of Electrodeposited Metallic and Inorganic Coatings3
B762Method for Variable Sampling of Metallic and Inor-ganic Coatings3
B849Speci?cation for Pre-Treatment of Iron or Steel for Reducing the Risk of Hydrogen Embrittlement3
B850Speci?cation for Post-Coating Treatments of Iron or
Steel for Reducing the Risk of Hydrogen Embrittlement3 B851Speci?cation for Automated Controlled Shot Peening of Metallic Articles Prior to Nickel,Autocatalytic Nickel, Chromium,or As A Final Finish3
D1193Speci?cation for Reagent Water5
D2670Method for Measuring Wear Properties of Fluid Lubricants(Falex Method)6
D2714Method for Calibration and Operation of an Alpha LFW-1Friction and Wear Testing Machine6
D3951Practice for Commercial Packaging7
D4060Test Method for Abrasion Resistance of Organic Coatings by the Taber Abraser8
E60Practice for Photometric Methods for Chemical Analy-sis of Metals9
E156Test Method for Determination of Phosphorus in High-Phosphorus Brazing Alloys(Photometric Method)10 E352Test Methods for Chemical Analysis of Tool Steels and Other Similar Medium-and High-Alloy Steel9
F519Test Method for Mechanical Hydrogen Embrittle-ment11
G5Practice for Standard Reference Method for Making Potentiostatic and Potentiodynamic Anodic Polarization Measurements12
G31Practice for Laboratory Immersion Corrosion Testing of Metals12
G59Practice for Conducting Potentiodynamic Polarization Resistance Measurements12
G85Practice for Modi?ed Salt Spray(Fog)Testing12
2.2Military Standards:
MIL-R-81841Rotary Flap Peening of Metal Parts13
MIL-S-13165Shot Peening of Metal Parts13
MIL-STD-105Sampling Procedures and Tables for Inspec-tion by Attribute13
2.3ISO Standards:
ISO4527Autocatalytic Nickel-Phosphorus Coatings—Speci?cation and Test Methods14
3.Terminology
3.1De?nition:
3.1.1signi?cant surfaces—those substrate surfaces which the coating must protect from corrosion or wear,or both,and that are essential to the performance.
3.2Other De?nitions—Terminology B374de?nes most of the technical terms used in this speci?cation.
4.Coating Classi?cation
4.1The coating classi?cation system provides for a scheme to select an electroless nickel coating to meet speci?c perfor-mance requirements based on alloy composition,thickness and hardness.
4.1.1TYPE describes the general composition of the de-posit with respect to the phosphorus content and is divided into ?ve categories which establish deposit properties(see Table1). N OTE1—Due to the precision of some phosphorus analysis methods a deviation of0.5%has been designed into this classi?cation scheme. Rounding of the test results due to the precision of the limits provides for an effective limit of4.5and9.5%respectively.For example,coating with a test result for phosphorus of9.7%would have a classi?cation of TYPE V,see Appendix X4,Alloy TYPEs.
4.2Service Condition Based on Thickness:
4.2.1Service condition numbers are based on the severity of the exposure in which the coating is intended to perform and minimum coating thickness to provide satisfactory perfor-mance(see Table2).
4.2.2SC0Minimum Service,0.1μm—This is de?ned by a minimum coating thickness to provide speci?c material prop-erties and extend the life of a part or its function.Applications
4Annual Book of ASTM Standards,V ol03.04.
5Annual Book of ASTM Standards,V ol11.01.
6Annual Book of ASTM Standards,V ol05.02.
7Annual Book of ASTM Standards,V ol09.02.
8Annual Book of ASTM Standards,V ol06.01.
9Annual Book of ASTM Standards,V ol03.05.
10Discontinued;see1992Annual Book of ASTM Standards,V ol03.05. 11Annual Book of ASTM Standards,V ol15.03.
12Annual Book of ASTM Standards,V ol03.02.
13Available from Standardization Documents Order Desk,Bldg.4Section D, 700Robbins Ave.,Philadelphia,PA19111-5094,Attn:NPODS.
14Available from American National Standards Institute,11W.42nd St.,13th Floor,New York,NY10036.
TABLE1Deposit Alloy Types
Type Phosphorus%wt
I No Requirement for Phosphorus
II1to3
III2to4
IV5to9
V10and above
TABLE2Service Conditions
Coating Thickness Requirements
Service Condition
Minimum Coating
Thickness
Speci?cation
μm in.(mm)
SC0Minimun Thickness0.10.000004()
SC1Light Service50.0002()
SC2Mild Service130.0005()
SC3Moderate Service250.001()
SC4Severe Service750.003(
)
include requirements for diffusion barrier,undercoat,electrical conductivity and wear and corrosion protection in specialized environments.
4.2.3SC1Light Service ,5μm—This is de?ned by a minimum coating thickness of 5μm for extending the life of the part.Typical environments include light-load lubricated wear,indoor corrosion protection to prevent rusting,and for soldering and mild abrasive wear.
4.2.4SC2Mild Service ,13μm—This is de?ned by mild corrosion and wear environments.It is characterized by indus-trial atmosphere exposure on steel substrates in dry or oiled environments.
4.2.5SC3Moderate Service ,25μm—This is de?ned by moderate environments such as non marine outdoor exposure,alkali salts at elevated temperature,and moderate wear.
4.2.6SC4Severe Service ,75μm—This is de?ned by a very aggressive environment.Typical environments would include acid solutions,elevated temperature and pressure,hydrogen sul?de and carbon dioxide oil service,high-temperature chlo-ride systems,very severe wear,and marine immersion.
N OTE 2—The performance of the autocatalytic nickel coating depends to a large extent on the surface ?nish of the article to be plated and how it was pretreated.Rough,non uniform surfaces require thicker coatings than smooth surfaces to achieve maximum corrosion resistance and minimum porosity.
4.3Post Heat Treatment Class —The nickel-phosphorus coatings shall be classi?ed by heat treatment after plating to increase coating adhesion and or hardness (see Table 3).4.3.1Class 1—As-deposited,no heat treatment.
4.3.2Class 2—Heat treatment at 260to 400°C to produce a minimum hardness of 850HK100.
4.3.3Class 3—Heat treatment at 180to 200°C for 2to 4h to improve coating adhesion on steel and to provide for hydrogen embrittlement relief (see section 6.6).
4.3.4Class 4—Heat treatment at 120to 130°C for at least 1h to increase adhesion of heat-treatable (age-hardened)alumi-num alloys and carburized steel (see Note 3).
4.3.5Class 5—Heat treatment at 140to 150°C for at least 1h to improve coating adhesion for aluminum,non age-hardened aluminum alloys,copper,copper alloys and beryl-lium.
4.3.6Class 6—Heat treatment at 300to 320°C for at least 1h to improve coating adhesion for titanium alloys.
N OTE 3—Heat-treatable aluminum alloys such as Type 7075can undergo microstructural changes and lose strength when heated to over 130°C.
5.Ordering Information
5.1The following information shall be supplied by the purchaser in either the purchase order or on the engineering drawing of the part to be plated:
5.1.1Title,ASTM designation number,and year of issue of this speci?cation.
5.1.2Classi?cation of the deposit by type,service condi-tion,class,(see 4.1,4.2and 4.3).
5.1.3Specify maximum dimension and tolerance require-ments,if any.
5.1.4Peening,if required (see
6.5).
5.1.5Stress relief heat treatment before plating,(see
6.3).5.1.6Hydrogen Embrittlement Relief after plating,(see 6.6).
5.1.7Signi?cant surfaces and surfaces not to be plated must be indicated on drawings or sample.
5.1.8Supplemental or Special Government Requirements such as,speci?c phosphorus content,abrasion wear or corro-sion resistance of the coating,solderability,contact resistance and packaging selected from Supplemental Requirements.5.1.9Requirement for a vacuum,inert or reducing atmo-sphere for heat treatment above 260°C to prevent surface oxidation of the coating (see S3).
5.1.10Test methods for coating adhesion,composition,thickness,porosity,wear and corrosion resistance,if required,selected from those found in Section 9and Supplemental Requirements.
5.1.11Requirements for sampling (see Section 8).
N OTE 4—The purchaser should furnish separate test specimens or coupons of the basis metal for test purposes to be plated concurrently with the articles to be plated (see 8.4).
6.Materials and Manufacture
6.1Substrate —Defects in the surface of the basis metal such as scratches,porosity,pits,inclusions,roll and die marks,laps,cracks,burrs,cold shuts,and roughness may adversely affect the appearance and performance of the deposit,despite the observance of the best plating practice.Any such defects on signi?cant surfaces shall be brought to the attention of the purchaser before plating.The producer shall not be responsible for coatings defects resulting from surface conditions of the metal,if these conditions have been brought to the attention of the purchaser.
6.2Pretreatment —Parts to be autocatalytic nickel plated may be pretreated in accordance with Guide B 656.A suitable method shall activate the surface and remove oxide and foreign materials,which may cause poor adhesion and coating poros-ity.
N OTE 5—Heat treatment of the base material may effect its metallur-gical properties.An example is leaded steel which may exhibit liquid or solid embrittlement after heat treatment.Careful selection of the pre and post heat treatments are recommended.
TABLE 3Classi?cation of Post Heat Treatment
CLASS Description
Temperature
(°C)
Time (h)
1No Heat Treatment,As Plated
2
Heat Treatment for Maximum Hardness TYPE I
260202851632084001TYPE II 350to 3801TYPE III 360to 3901TYPE IV 365to 4001TYPE V
375to 40013Hydrogen Embrittlement and Adhesion on Steel
180to 2002to 44Adhesion,Carburized Steel and Age Hardened Aluminum 120to 1301to 65Adhesion on Beryllium and Aluminum
140to 1501to 26
Adhesion on Titanium
300–320
1–4
6.3Stress Relief:
6.3.1Pretreatment of Iron and Steel for Reducing the Risk of Hydrogen Embrittlement—Parts that are made of steel with ultimate tensile strength of greater than1000Mpa(hardness of 31HRC or greater),that have been machined,ground,cold formed,or cold straightened subsequent to heat treatment,shall require stress relief heat treatment when speci?ed by the purchaser,the tensile strength to be supplied by the purchaser, Speci?cation B849may be consulted for a list of pre-treatments that are widely used.
6.3.2Peening—Peening prior to plating may be required on high-strength steel parts to induce residual compressive stresses in the surface,which can reduce loss of fatigue strength and improve stress corrosion resistance after plating. (See Supplementary Requirements).
6.3.3Steel parts which are designed for unlimited life under dynamic loads shall be shot peened or rotary?ap peened.
N OTE6—Controlled shot peening is the preferred method because there are geometry’s where rotary?ap peening is not effective.See S11.2. 6.3.3.1Unless otherwise speci?ed,the shot peening shall be accomplished on all surfaces for which the coating is required and all immediate adjacent surfaces when they contain notches,?llets,or other abrupt changes of section size where stresses will be concentrated.
6.4Racking—Parts should be positioned so as to minimize trapping of hydrogen gas in cavities and holes,allowing free circulation of solution over all surfaces to obtain uniform coating thickness.The location of rack or wire marks in the coating shall be agreed upon between the producer and purchaser.
6.5Plating Process:
6.5.1To obtain consistent coating properties,the bath must be monitored periodically for pH,temperature,nickel and hypophosphite.Replenishments to the plating solution should be as frequent as required to maintain the concentration of the nickel and hypophosphite between90and100%of set point. The use of a statistical regimen to establish the control limits and frequency of analysis may be employed to ensure quality deposits are produced.
6.5.2Mechanical movement of parts and agitation of the bath is recommended to increase coating smoothness and uniformity and prevent pitting or streaking due to hydrogen bubbles.
6.6Post Coating Treatment for Iron and Steel for Reducing the Risk of Hydrogen Embrittlement—Parts that are made of steel with ultimate tensile strengths of1000Mpa(hardness of 31HRC or greater),as well as surface hardened parts,shall require post coating hydrogen embrittlement relief baking when speci?ed by the purchaser,the tensile strength to be supplied by the purchaser.Speci?cation B850may be con-sulted for a list of post treatments that are widely used.
6.6.1Heat treatment shall be performed preferably within1
h but not more than3h of plating on plated after plating of steel parts to reduce the risk of hydrogen embrittlement.In all cases,the duration of the heat treatment shall commence from the time at which the whole of each part attains the speci?ed temperature.
6.6.2High-strength steel parts with actual tensile strengths greater than1000MPa(corresponding hardness values300 HV10,303HB or31HRC)and surface hardened parts shall be processed after coating in accordance with Speci?cation B850.
6.7Heat Treatment After Plating to Improve Adhesion—To improve the adhesion of the coating to various substrates,the heat treatments in Table3should be performed as soon as practical after plating(see4.3).
6.8Heat Treatment After Plating to Increase Hardness: 6.8.1To increase the hardness of the coating a heat treat-ment of over260°C is required.Table3describes the heat treatment for maximum hardness.
6.8.2See Appendixes3and4and Guide B656;Figs.X1.2 and Figs.X1.3.
6.8.3A heat treatment at260°C for greater than20h should be used to reduce the loss of surface hardness and strength of some ferrous basis metals.Avoid rapid heating and cooling of plated parts.Sufficient time must be allowed for large parts to reach oven temperature.
N OTE7—The length of time to reach maximum hardness varies with the phosphorus content of the deposit.High phosphorus deposits may require longer time or a higher temperature,or both.Individual alloys should be tested for maximum hardness attainable,especially for condi-tions of lower temperatures and longer times.
N OTE8—Inert or reducing atmosphere or vacuum sufficient to prevent oxidation is recommended for heat treatment above260°C.Do not use gas containing hydrogen with high-strength steel parts.
7.Requirements
7.1Process—The coating shall be produced from an aque-ous solution through chemical reduction reaction.
7.2Acceptance Requirements—These requirements are placed on each lot or batch and can be evaluated by testing the plated part.
7.2.1Appearance:
7.2.1.1The coating surface shall have a uniform,metallic appearance without visible defects such as blisters,pits, pimples,and cracks(see9.2).
7.2.1.2Imperfections that arise from surface conditions of the substrate which the producer is unable to remove using conventional pretreatment techniques and that persist in the coating shall not be cause for rejection(see 6.1).Also, discoloration due to heat treatment shall not be cause for rejection unless special heat treatment atmosphere is speci?ed (see section5.1.9).
7.2.2Thickness—The thickness of the coating shall exceed the minimum requirements in Table2as speci?ed by the service condition agreed to prior to plating(see9.3).After coating and if speci?ed,the part shall not exceed maximum dimension on signi?cant surface(see section5.1.3).
N OTE9—The thickness of the coating cannot be controlled in blind or small diameter deep holes or where solution circulation is restricted. 7.2.3Adhesion—The coating shall have sufficient adhesion to the basis metal to pass the speci?ed adhesion test(see9.4 and Test Methods B571).
7.2.4Porosity—The coatings shall be essentially pore free when tested according to one of the methods of9.6.The test method,the duration of the test,and number of allowable spots per unit area shall be speci?ed(see section5.1.10and
9.6).
7.3Quali?cation Requirements—These requirements are placed on the deposit and process and are performed on specimens to qualify the deposit and plating process.The tests for these quali?cation requirements shall be performed monthly or more frequently.
7.3.1Composition—Type II,III,IV,V deposits shall be analyzed for alloy composition by testing for phosphorus(see 9.1).The weight percent of phosphorus shall be in the range designated by type classi?cation(see4.1).
7.3.2Microhardness—The microhardness of Class2depos-its shall be determined by Test Method B578(Knoop).For Class2coatings,the microhardness shall equal or exceed a minimum of850(HK100(or equivalent Vickers)(see4.3and 9.5).The conversion of Vickers to Knoop using Tables E140 is not recommended.
7.3.3Hydrogen Embrittlement—The process used to de-posit a coating onto high strength steels shall be evaluated for hydrogen embrittlement by Test Method F519.
8.Sampling
8.1The purchaser and producer are urged to employ statis-tical process control in the coating process.Properly performed this will ensure coated products of satisfactory quality and will reduce the amount of acceptance inspection.
8.1.1Sampling plans can only screen out unsatisfactory products without assurance that none of them will be accepted.
(7)
8.2The sampling plan used for the inspection of a quantity of coated parts(lot)shall be Test Method B602unless otherwise speci?ed by purchaser in the purchase order or contract(see section5.1.11and S.11.1).
N OTE10—Usually,when a collection of coated parts(the inspection lot
8.2)is examined for compliance with the requirements placed on the parts
a relatively small number of parts,the sample,is selected at random and inspected.The inspection lot is then classi?ed as complying or not complying with the requirements based on the results of the inspection sample.The size of the sample and the criteria of compliance are determined by the application of statistics.The procedure is known as sampling inspection.Three standards Test Method B602,Guide B697, and Test Method B762contain sampling plans that are designed for the sampling inspection of coatings.
Test Method B602contains four sampling plans,three for use with tests that are nondestructive and one for use with tests that are destructive.The purchaser and producer may agree on the plan(s)to be used.If they do not, Test Method B602identi?es the plan to be used.
Guide B697provides a large number of plans and also gives guidance on the selection of a plan.When Guide B697is speci?ed,the purchaser and producer need to agree on the plan to be used.
Test Method B762can be used only for coating requirements that have a numerical limit,such as coating thickness.The last must yield a numerical value and certain statistical requirements must be met.Test Method B762contains several plans and also gives instructions for calculating plans to meet special needs.The purchaser and producer may agree on the plan(s)to be used.If they do not,Test Method B762 identi?es the plan to be used.
An inspection lot shall be de?ned as a collection of coated parts which are of the same kind,that have been produced to the same speci?cation, that have been coated by a single producer at one time or approximately the same time under essentially identical conditions,and that are submit-ted for acceptance or rejection as a group.
8.3All specimens used in the sampling plan for acceptance tests shall be made of the same basis material and in the same metallurgical condition as articles being plated to this speci?-cation.
8.4All specimens shall be provided by the purchaser unless otherwise agreed to by the producer.
N OTE11—The autocatalytic nickel process is dynamic and a daily sampling is recommended.For Coatings requiring alloy analysis and corrosion testing weekly sampling should be considered as an option. 9.Test Methods
9.1Deposit Analysis for Phosphorus:
9.1.1Phosphorus Determination—Determine mass% phosphorus content according to Practice E60,Test Methods E352,or Test Method E156on known weight of deposit dissolved in warm concentrated nitric acid.
9.1.2Composition can be determined by atomic absorption, emission or X-ray?uorescence spectrometry.
N OTE12—Inductively coupled plasma techniques can determine the alloy to within0.5%.The following analysis wavelength lines have been used with minimum interference to determine the alloy.
Ni216.10nm Cd214.44nm Fe238.20nm
P215.40nm Co238.34nm Pb283.30nm
P213.62nm Cr284.32nm Sn198.94nm
Al202.55nm Cu324.75nm Zn206.20nm
9.2Appearance—Examine the coating visually for compli-ance with the requirements of7.2.1.
9.3Thickness:
N OTE13—Eddy-current type instruments give erratic measurements due to variations in conductivity of the coatings with changes in phosphorus content.
9.3.1Microscopical Method—Measure the coating thick-ness of a cross section according to Test Method B487.
N OTE14—To protect the edges,electroplate the specimens with a minimum of5μm of nickel or copper prior to cross sectioning.
9.3.2Magnetic Induction Instrument Method—Test Method B499is applicable to magnetic substrates plated with auto-catalytic nickel deposits,that contain more than11mass% phosphorus(not ferromagnetic)and that have not been heat-treated.The instrument shall be calibrated with deposits plated in the same solution under the same conditions on magnetic steel.
9.3.3Beta Backscatter Method—Test Method B567is only applicable to coatings on aluminum,beryllium,magnesium, and titanium.The instrument must be calibrated with standards having the same composition as the coating.
N OTE15—The density of the coating varies with its mass%phospho-rus content(See Appendix X2).
9.3.4Micrometer Method—Measure the part,test coupon, or pin in a speci?c spot before and after plating using a suitable micrometer.Make sure that the surfaces measured are smooth, clean,and dry.
9.3.5Weigh,Plate,Weigh Method—Using a similar sub-strate material of known surface area,weigh to the nearest milligram before and after plating making sure that the part or coupon is dry and at room temperature for each
measurement.
Calculate the thickness from the increase in weight,speci?c gravity,and area as follows:
coating thickness,μm510W/~A3D!(1) where:
W=weight gain in milligrams,
A=total surface area in square centimetres,and
D=grams per cubic centimetres(see Appendix X2).
9.3.6Coulometric Method—Measure the coating thickness in accordance with Test Method B504.The solution to be used shall be in accordance with manufacturer’s recommendations. The surface of the coating shall be cleaned prior to testing(see Note14).
9.3.6.1Calibrate standard thickness specimens with depos-its plated in the same solution under the same conditions. 9.3.7X-Ray Spectrometry—Measure the coating thickness in accordance with Test Method B568.The instrument must be calibrated with standards having the same composition as the coating.
N OTE16—This method is only recommended for deposits in the as-plated condition.The phosphorus content of the coating must be known to calculate the thickness of the deposit.Matrix effect due to the distribution of phosphorus in layers of the coating also effect the measurement accuracy and require that calibration standards be made under the same conditions as the production process.
9.4Adhesion:
9.4.1Bend Test(Test Methods B571)—A sample specimen is bent180°over a mandrel diameter43the thickness(10mm minimum)of the specimen and examined at43power magni?cation for?aking or separation at the interface.Fine cracks in the coating on the tension side of the bend are not an indication of poor adhesion.Insertion of a sharp probe at the interface of the coating and basis metal to determine the adhesion is suggested.
N OTE17—Appropriate test specimens are strips approximately25to50 mm wide,200to300mm long and3to6mm thick.
9.4.2Impact Test—A spring-loaded center punch with a point having2to3mm radius is used to test adhesion of the coating on nonsigni?cant surfaces of the plated part.Make three closely spaced indentations and examine under103 magni?cation for?aking or blistering of the coating,which is cause for rejection.
9.4.3Thermal Shock—The coated part is heated to200°C in an oven and then quenched in room temperature water.The coating is examined for blistering or other evidence of poor adhesion at43magni?cation.
9.5Microhardness—The microhardness of the coating can be measured by Test Method B578using Knoop indenter and is reported in Knoop Hardness Number(HK).It will vary depending on loads,type of indenter,and operator.A100g load is recommended.The rhombic Knoop indenter gives higher hardness readings than the square-base pyramidal Vickers diamond indenter for100to300g loads,see Ref(6).For maximum accuracy,a minimum coating thickness of75μm is recommended.Conversions of Vickers or Knoop hardness number to Rockwell C is not recommended.
N OTE18—On thick(75μm+)coatings on steel a surface microhardness determination is permissible.
9.6Porosity—There is no universally accepted test for porosity.When required,one of the following tests can be used on the plated part or specimen.
9.6.1Ferroxyl Test for Iron Base Substrates—Prepare the test solution by dissolving25g of potassium ferricyanide and 15g of sodium chloride in1L of distilled water.After cleaning,immerse the part for30s in the test solution at25°C. After rinsing and air drying,examine the part for blue spots, which form at pore sites.
9.6.2Boiling Water Test for Iron-Base Substrates—Completely immerse the part to be treated in a vessel?lled with aerated water at room temperature.Apply heat to the beaker at such a rate that the water begins to boil in not less than15min,nor more than20min after the initial application of heat.Continue to boil the water for30min.Then remove the part,air dry,and examine for rust spots,which indicate pores. N OTE19—Aerated water is prepared by bubbling clean compressed air through distilled water by means of a glass diffusion disk at room temperature for12h.The pH of the aerated water should be6.7+0.5.
9.6.3Aerated Water Test for Iron-Base Substrates—Immerse the part for4h in vigorously aerated Type IV or better water(see Speci?cation D1193)at2562°C temperature and then examine the part for rust spots.
9.6.4Alizarin Test for Aluminum Alloys—Wipe the plated part or specimen with10mass%sodium hydroxide solution. After3min contact,rinse,and apply a solution of alizarin sulfonate prepared by dissolving1.5g of methyl cellulose in90 mL of boiling water to which,after cooling,0.1g sodium alizarin sulfonate,dissolved in5mL of ethanol is added.After 4min contact,apply glacial acetic acid until the violet color disappears.Any red spots remaining indicate pores.
9.6.5Porosity Test for Copper Substrates—Wipe the plated part or specimen with glacial acetic acid.After3min,apply a solution of potassium ferrocyanide prepared by dissolving1g of potassium ferrocyanide and1.5g methyl cellulose in90mL of boiling distilled water.The appearance of brown spots after 2min indicate pores.
9.7Other Test Methods—Test methods which have been developed that are equal to or better than these may be substituted.The precision and bias requirements will vary for each type of test.If an alternate test is speci?ed it shall be agreed upon between the producer and the purchaser.
10.Rejection and Rehearing
10.1Part(s)that fail to conform to the requirements of this standard may be rejected.Rejection shall be reported to the producer promptly in writing.In the case of dissatisfaction occurs with the results of a test,the producer may make a claim for a hearing.Coatings that show imperfections may be rejected.
11.Certi?cation
11.1When speci?ed in the purchase order or contract,the purchaser shall be furnished certi?cation that the samples representing each lot have been processed,tested and inspected as directed in this speci?cation and the requirements have
been
met.When speci?ed in the purchase order or contract,a report
of the test results shall be furnished.
12.Keywords
12.1autocatalytic;chemical nickel;coatings;conductive;
corrosion resistance;electroless;functional;nickel;nickel
phosphorus;wear resistance
SUPPLEMENTARY REQUIREMENTS
The following supplementary requirements shall apply only when speci?ed by the purchaser in the
contract or order.
S1.1Shot Peening—When speci?ed by the purchaser in the ordering information,the part(s)shall be shot peened prior to plating in accordance with Speci?cation B851or MIL-S-13165.
S1.2Composition—When speci?ed by the purchaser in the ordering information the phosphorus content shall be main-tained in the deposit to within1%.Use the test methods described in9.1.
S1.3Inert Atmosphere—When speci?ed by the purchaser in the ordering information,the coating shall be heat treated in a vacuum,inert,or reducing atmosphere to prevent surface oxidation of the coating.
S1.4Hydrogen Embrittlement—When speci?ed by the pur-chaser in the ordering information the plating process shall be evaluated at the time of processing parts for hydrogen em-brittlement using Test Method F519.
S1.5Abrasive Wear—When speci?ed by the purchaser in the ordering information,the coating shall be tested for abrasion wear resistance using the method in Appendix X1of this speci?cation.The coating shall meet a maximum wear rate which is speci?ed by the purchaser and agreed to by the producer.
S1.6Adhesive Wear—When speci?ed by the purchaser in the ordering information,the coating shall be tested for adhesive wear resistance using Test Method D2714or Test Method D2670.The wear rate shall be speci?ed by the purchaser and agreed to by the producer.
S1.7Contact Resistance—When speci?ed by the purchaser in the ordering information,the coating shall be tested for contact resistance using Test Method B667.
S1.8Solderability—When speci?ed by the purchaser in the ordering information,the unaged coating shall pass Test Method B678on solderability.
S1.9Corrosion Resistance—When speci?ed by the pur-chaser in the ordering information the coating shall pass any special corrosion tests agreed to by the producer.The corrosion resistance of the coating to a speci?c liquid medium can be determined by means of immersion tests(see Practice G31)or electrochemical test(see Practices G5and G59).
S1.10Pitting Corrosion Resistance—Use Method G85 (acetic acid-salt spray test),Method B368(copper-accelerated acetic acid-salt spray,CASS),or Method B380(Corrodkote) to evaluate the corrosion resistance of the coating to pitting. S1.11Special Government Requirements:
S1.11.1Sampling—Part(s)plated for the US Government and Military use shall use MIL-STD-105as the sampling plan. S1.11.2Shot Peening—High strength steel part(s)pro-cessed for US Government and Military use shall be shot peened in accordance with MIL-S-13165or rotary?ap peened in accordance with MIL-R-81841.(see Note6).
S1.11.3Packaging—Parts shall be packaged in accordance with Practice D3951.
APPENDIXES
(Nonmandatory Information)
X1.TABER ABRASER WEAR TEST METHOD
X1.1Scope
X1.1.1This test method will evaluate the resistance of the coating to abrasive wear.The test is performed by rotating a plated panel under rotating rubber wheels and weighing the panel after each1000cycles for weight loss.Duration of the test is6000cycles and it can be extended to25000cycles for more complete results.
N OTE X1.1—Variation in results have been attributed to the humidity in the laboratory and the storage conditions of the CS-10wheels.Care should be taken to control the humidity between tests.
X1.1.2The results are variable between tests and therefore three plated test specimens should be tested to6000cycles each.The results should be averaged without the?rst1000 cycles and the abrasion wear resistance is reported as the weight loss in mg/1000cycles(Taber Wear
Index).
X1.2Apparatus
X1.2.1Taber Abraser Wear Testing Unit—The unit must be capable of loading with1000g load and operating with a vacuum.
X1.2.2Abrasion Wheels—Use CS-10(resilient rubber) Taber wheels.To reface the wheels use CS-11discs from Taber. The hardness of CS-10wheels can change with time and can effect the reproducibility of results(see Test Method D4060). X1.2.3Test Specimens—Test specimens shall be made from20gage CR steel4by4in.(100by100by1.3mm)with a0.250(6.35mm)hole in the center.Test specimens are available from Taber.
X1.2.4Analytical Balance—Scale which is capable of mea-suring to150g60.1mg.
X1.3Procedure
X1.3.1Plate three specimens with0.001in.(25μm)of nickel phosphorus coating.
X1.3.2Wear test the specimens.For each of the three specimens complete the following steps:
X1.3.2.1Run the CS-10wheels on the coating for1000 cycles to remove any surface roughness.The wheels shall be loaded with1000g with a vacuum on high for the entire test. X1.3.2.2Cool and weigh the specimen to the nearest0.1 mg.
X1.3.2.3Dress the CS-10wheels with a CS-11disc for50 cycles.
X1.3.2.4Abrasion test the coating with1000g load for 1000cycles.
X1.3.2.5Repeat X1.3.2.2,X1.3.2.3and X1.3.2.4until a total of6000cycles have been accomplished for each speci-men.
X1.4Reporting
X1.4.1Determine the average weight loss in milligrams for each specimen per1000cycles Taber Wear Index and the mean weight loss per1000cycles for all specimens.Report the mean and standard deviation for the
coating.
X2.DENSITY OF AUTOCATALYTIC NICKEL DEPOSITS
FIG.X2.1Density of Autocatalytic Nickel Phosphorus Alloy Summary of Reported Values
X3.HARDNESS VERSUS HEAT TREATMENT
X4.ALLOY TYPES
N OTE X4.1—These different alloy TYPEs are produced from processes which are speci?cally formulated and controlled.Additional requirements for internal stress,purity,and elongation may be necessary for some applications.
X4.1The physical differences of these TYPEs provide for a wide variation in performance in wire bonding,contact resistance,machineability,lubricity,reactivation and melting
point.These differences are produced by micro structural differences between Ni +Ni3P and Ni3P.These differences also effect non-destructive thickness testing by X-Ray and magnetic means.Careful attention to the selection of TYPE will insure optimum performance of the deposit in the intended
application.
FIG.X3.1Hardness of Autocatalytic Nickel Phosphorus Versus Heat Treatment Versus
Phosphorus
X5.SUMMARY PROGRAM 14
X5.1Results of 110Month Exposure of Autocatalytic Nickel Deposits at Kure Beach,North Carolina:
X5.1.1Program 14is part of an ongoing marine exposure testing process at the 75m site at LaQue Center for Corrosion Technology,Wrightsville,NC (Kure Beach).The program called for the plating of both Type IV and Type V deposits on standard smooth and ground steel Q Panels.
X5.1.2There were nine different sources of deposits,each providing ?ve lots of ?ve panels.The program involved plating 12.5,25,and 75μm thicknesses on smooth and ground surface and one smooth lot heat treated for hardness at 550°C for 2h.The heat treatment temperature was considerably higher than typical processing and was chosento evaluate the formation of diffusion products of iron,nickel and phosphorus.
X5.1.3The following matrix of test panels were prepared and exposed with subsequent analysis for alloy and thickness.Panels were rated at Kure Beach each year by a team from ASTM Committee B8using Practice B 537.
X5.1.4The interpretation of the results of these exposure test should be made on the basis of general performance of the coating on panels.Base metal condition,undercoats,surface preparation,and post processing all have a signi?cant effect on the performance and should be given careful consideration when designing the part and pretreatment processing
sequence.
FIG.X4.1Selected Properties of As Plated Autocatalytic Nickel Phosphorus Coatings by Phosphorus
Content
REFERENCES
(1)Symposium on Electroless Nickel Plating,ASTM STP 265,ASTM,1959.
(2)Engineering Properties of Electroless Nickel ,The International Nickel Co.,Inc.,New York,NY .
(3)Gawrilov,C.G.,Chemical (Electroless)Nickel Plating ,Portcullis Press,London,1974.
(4)Safranek,W.H.,The Properties of Electrodeposited Metals and Alloys ,The American Electroplaters and Surface Finishers Society,
12644Research Parkway,Orlando,FL 32826,1986Chapter 23.(5)Mallory G.,and Hajdu J.“Electroless Plating,”AESF 12644Research Parkway,Orlando,FL 32826,1990.
(6)Parker,K.,“Hardness and Wear Resistance Tests of Electroless Nickel Deposits,”Plating ,V ol 61,September 1974.
(7)Parker,K.,“Effects of Heat Treatment on the Properties of Electroless Nickel Deposits,”Plating and Surface Finishing ,V ol 68,December 1981.
TABLE X5.1Results of 110Month Exposure of Autocatalytic (Electroless)Nickel Deposits at Kure Beach,North Carolina A
Deposit Type
Source
Lot
Surface
Heat Treatment Thickness,μm Target Thickness,μm Actual
Phosphorus Alloy %wt
Practice B 537Ratings 110Months ICP
EDAX
1Smooth No 12.5 3.663.02Smooth No 259.260.3V G
3Smooth No 7580.510.510.9
10604Smooth Yes 259.260.35Ground No 257.860.41Smooth No 12.50.0602Smooth No 258.060V E
3Smooth No 757710.010.2
9.860.44Smooth Yes 258.260.85Ground No 25 4.260.41Smooth No 12.5 6.861.32Smooth No 25 6.260.4V C
3Smooth No 75469.910.4
8.861.14Smooth Yes 25 6.861.35Ground No 250.0601Smooth No 12.50.0602Smooth No 25 5.860.4IV J
3Smooth No 759.0
9.661.14Smooth Yes 257.0605Ground No 25 1.0621Smooth No 12.50.660.52Smooth No 257.460.9IV H
3Smooth No 758.9
10.0604Smooth Yes 25 4.861.15Ground No 250.0601Smooth No 12.50.0602Smooth No 25 1.861.6IV B
3Smooth No 75798.37.3
6.061.04Smooth Yes 25 5.0605Ground No 250.0601Smooth No 12.50.0602Smooth No 250.060IV D
3Smooth No 75778.29.5
5.061.44Smooth Yes 25 5.460.55Ground No 250.0601Smooth No 12.50.0602Smooth No 250.060IV K
3Smooth No 757.5
0.660.84Smooth Yes 25 5.662.85Ground No 250.0601Smooth No 12.50.0602Smooth No 250.260.4IV I
3Smooth No 75807.1
0.460.54Smooth Yes 25 4.660.85Ground
No
25
0.060
A
The conclusions from this marine exposure program have been summarized by Dr.George DiBari of INCO in his paper Marine Corrosion Performance of EN Coating on Steel,Final Report on ASTM Program 14which was presented at EN91Conference,Product
Finishing.
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钢铁的化学镀镍磷
钢铁的化学镀镍磷 金属1002 陈浩 3100702039 摘要：本文简要介绍了钢铁化学镀镍磷的原理与工艺流程，简述了镀层的性能及技术指标，随之分析了影响镀层性能的主要因素，并据此给出了工艺中的除锈配方和镀液配方，最后对试验参数进行了测定与比较，得出了一定的结论。 关键词：化学镀镀镍磷表面强化耐磨耐腐蚀性 一．前言 化学镀镍磷工艺是近年来迅速发展起来的一种新型表面保护和表面强化技术手段，具有广泛的应用前景。目前化学镀镍磷合金已广泛地应用在石油化工、石油炼制、电子能源、汽车、化工等行业。石油炼制和石油化工是其最大的市场，并且随着人们对这一化学镀特性的认识，它的应用也越来越广泛，主要用在石油炼制、石油化工的冷换设备上，化学镀镍磷能够显著提高设备的耐磨、耐蚀性能，延长其寿命，性能优于目前使用的有机涂料，而且适用于碳钢、铸铁、有色金属等不同基材。 二．实验原理 化学镀镍磷合金是一种在不加电流的情况下，利用还原剂在活化零件表面上自催化还原沉积得到镍磷镀层的方法。其主要反应为应用次亚磷酸钠还原镍离子为金属镍，即在水溶液中镍离子和次亚磷酸根离子碰撞时，由于镍触媒作用析出原子态氢，而原子态氢又被催化金属吸附并使之活化，把水溶液中的镍离子还原为金属镍形成镀层，另外次亚磷酸根离子由于在催化表面析出原子态氢的作用，被还原成活性磷，与镍结合形成Ni-P合金镀层。 以次磷酸钠为还原剂的化学镀镍磷工艺，其反应机理，现普遍被接受的是“原子氢态理论”和“氢化物理论”。下面介绍“原子氢态理论”，其过程可分为以下四步： 1、化学沉积镍磷合金镀液加热时不起反应，而是通过金属的催化作用，次亚磷酸根在水溶液中脱氢而形成亚磷酸根，同时放出初生态原子氢。 H 2PO 2 -+H 2 O→HPO 3 -+2H+H-
化学镀镍磷合金英文文献
An investigation on effects of heat treatment on corrosion properties of Ni–P electroless nano-coatings Taher Rabizadeh,Saeed Reza Allahkaram *,Arman Zarebidaki School of Metallurgy and Materials Engineering,University College of Engineering,University of Tehran,P.O.Box 11155-4563,Tehran,Iran a r t i c l e i n f o Article history: Received 19January 2010Accepted 15February 2010 Available online 17February 2010Keywords:C.Coating C.Heat treatment E.Corrosion a b s t r a c t Electroless Ni–P coatings are recognized for their excellent properties.In the present investigation elec-troless Ni–P nano-crystalline coatings were prepared.X-ray diffraction technique (XRD),scanning elec-tron microscopy (SEM),potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)were utilized to study prior and post-deposition vacuum heat treatment effects on corrosion resis-tance together with the physical properties of the applied coatings. X-ray diffraction (XRD)results indicated that the As-plated had nano-crystalline structure.Heat treat-ment of the coatings produced a mixture of polycrystalline phases.The highest micro-hardness was achieved for the samples annealed at 600°C for 15min due to the formation of an inter-diffusional layer at the substrate/coating interface. Lower corrosion current density values were obtained for the coatings heat treated at 400°C for 1h.EIS results showed that proper heat treatments also enhanced the corrosion resistance,which was attributed to the coatings’structure improvement. ó2010Elsevier Ltd.All rights reserved. 1.Introduction Since the invention of electroless plating technology in 1946by A.Brenner and G.Riddell,electroless nickel (EN)coatings have been actively and widely studied [1,2]. Nano-crystalline Ni–P alloys show a high degree of hardness,wear resistance,low friction coef?cient,non-magnetic behavior and high electro-catalytic activity.Today such Ni–P alloys are widely used in the electronic industry as under-layer in thin ?lm memory disks and in a broad range of other evolving technological applications.It is generally accepted that only nano-crystalline al-loys –irrespective of the way of production –show high corrosion resistance.Indeed,electrodeposited Ni–P alloys with crystalline structure (6–11at.%P)showed anodic dissolution in 0.1M NaCl.On nano-crystalline samples (17–28at.%P)a current arrest was found instead [3–5]. To explain high corrosion resistance of Ni–P electroless coatings different models have been proposed,but the issue is still under discussion:a protective nickel phosphate ?lm,the barrier action of hypophosphites (called ‘‘chemical passivity”),the presence of phosphides,a stable P-rich amorphous phase or the phosphorus enrichment of the interface alloy-solution were proposed.Note that such phosphorus enrichment at the interface was reported by some of the authors to explain the outstanding corrosion resis-tance of Fe70Cr10P13C7amorphous alloys [5]. Electroless Ni–P alloys are thermodynamically unstable and eventually form stable structures of face-centered cubic (fcc)Ni crystal and body-centered tetragonal (bct)nickel phosphide (Ni 3P)compounds.Different results have been reported regarding the microstructures in the As-deposited condition and the stable phases after heat treatments.For low P and medium P alloys,nickel crystal precipitated ?rstly and Ni 3P followed;however,Ni 3P and (or)Ni x P y compounds such as Ni 2P,Ni 5P 2,Ni 12P 5,and Ni 7P 3occur ?rstly in high P alloys [6–8]. In general,the hardness of the electroless Ni–P coatings can be improved by appropriate heat treatment,which can be attributed to ?ne Ni crystallites and hard inter-metallic Ni 3P particles precip-itated during crystallization of the amorphous phase [8–10]. The main reasons for heat treatment are:(1)to eliminate any hydrogen embrittlement in the basic metal,(2)to increase deposit hardness or abrasion resistance,(3)to increase deposit adhesion in the case of certain substrate and (4)to increase temporary corro-sion resistance or tarnish resistance [11]. The crystallization and phase transformation behavior of elec-troless-plated Ni–P deposits during thermal processing has also been the subject of various investigations;it has been shown that different alloy compositions and heat treatment conditions could affect both the corrosion resistance and crystallization behavior of the deposit [8]. 0261-3069/$-see front matter ó2010Elsevier Ltd.All rights reserved.doi:10.1016/j.matdes.2010.02.027 *Corresponding author.Tel./fax:+982161114108.E-mail address:akaram@ut.ac.ir (S.R.Allahkaram). Materials and Design 31(2010) 3174–3179 Contents lists available at ScienceDirect Materials and Design j o u r n a l h o m e p a g e :w w w.e l s e vier.c om/loc ate/mat des
化学镀镍磷合金最新进展
化学镀镍磷合金研究进展 摘要：化学镀镍磷合金镀层由于其优良的耐磨耐蚀、无磷和镀层均匀等特性，在许多领域得到广泛应 用。本文综述了化学镀镍磷合金在各方面的研究进展，对化学镀镍磷工艺、沉积过程及沉积机理、镀层组织结构、性能及应用作了详细论述。 关键词化学镀，镍磷合金，组织结构，性能 Abstract Electroless despite of nickel phosphorus alloy has been widely used in diverse fieldsfortheiruniquecombinationsofpropertiessuchasrestistance,corrosionesistance,non-magnetism and uniformity of coating thick-ness. Research development of electroless Ni-P deposit on various aspect is summarized in this paper.Special attention has been focused on deposition process,depositionmechanism,microstructure,as well as some properties and applications of the despoists. Key words Electrolessdepoists,Ni-P alloy,Microstructure,Property 1概述 化学镀是用还原剂还原溶液中的络合金属离子，在催化活化表面获得所需的金属镀层，而赋予基体材料本身并不具有的表面性能。化学镀具有如下特点:（l）优良的深镀及均镀能力；（2）适用范围广，可在常用金属及经特殊处理的非导体和半导体材料表面沉积出镀层；（3）设备简单，操作方便；（4）镀层致密，无针孔，具有优良的耐蚀性；（5）镀层具有较高硬度和良好的耐磨性；（6）镀层成分可以根据需要改变镀液类型及操作条件来加以选择。化学镀镍由于其独特的沉积特性和优越的物理、化学和力学性能而在石油、化工、航空、航天、电子、计算机、汽车等工业领域获得广泛应用。 目前，得到深人研究及广泛应用的是化学镀镍层。在美国、日本、欧洲等国家都有商品化学镀镍液出售，并已形成门类齐全的商品系列，镍用于化学镀的消耗量每年以15%的速度增长。化学镀镍分Ni一P、Ni一B两类工艺，本文将主要探讨以次亚磷酸钠为还原剂的化学镀Ni一P层的各方面研究。 2化学镀镍磷工艺 60年代初，具有广泛适用性的专利性化学镀镍工艺进人了美国市场，当时的产品都是中等磷含量[5%一8%P（质量分数）]镀层，该镀层通常采用了含硫稳定剂或重金属离子，在各种性能上有一定的局限性。70年代后期到80年代，研究重点转向高磷化学镀镍层[9%一12%P（质量分数）]，该种镀层具有非晶态结构，而赋予镀层极佳的耐蚀性，改善了压应力，延长了疲劳寿命，并具有非磁特性，而深得广大工程技术人员的青睐。近期人们研究发现，低磷镀层[1%一5%P（质量分数）]具有高的镀态硬度和优良的耐碱蚀特性，在许多应用场合可用来代替硬铬及镍硼镀层，特别适用于要求耐磨性而不能经受高温热处理的材料（如铝及铝合金）,显示出广阔的开发应用前景。 化学镀Ni-P工艺按溶液pH值可分为酸性和碱性两大体系，镀液的主要成分是NISO4·6H2O和NaH2PO2·2H2O，同时为了保证镀液稳定和镀层质量，镀液中还必须加入一定量的络合剂、加速剂、稳定剂、光亮剂等。只有在正确选择了各种添加剂及含量的情况下，才能获得优良的化学镀镍工艺，要求工艺不仅有较快的沉积速度，而且镀液稳定性好，使用周期长，同时还要保证镀层优良的使用性能。 3化学镀镍磷沉积过程与沉积机理 3.1化学镀镍磷的沉积速度及镀层组成 化学镀镍沉积反应的动力学同时控制着沉积速率和镀层组成。对于化学镀镍这样一个含有多种化学成分的复杂反应体系，人们广泛研究了各种操作参数及溶液组成对沉积速度和镀
镁合金表面化学镀镍
镁合金表面化学镀镍处理 摘要：本实验研究以硫酸镍为主盐的AZ91镁合金化学镀镍。选择适合的工艺流程、对实验材料进行化学镀镍处理、对化学镀镍层进行宏观或微观形貌观察、测量镀镍层的硬度、检验化学镀镍层的耐蚀性。实验表明，用该工艺能够在AZ91合金表面上生成化学镀镍层，镀层表面为胞状结构而且胞表面的晶界和缺陷较多，化学镀镍层较好地提高了镁合金的耐腐蚀性能，硬度有所提高。 关键词：AZ91D镁合金化学镀镍腐蚀性硬度 The chemical nickel plated of the surface of Magnesium alloy Abstract: The experimental study the nickel plating of Magnesium alloys of AZ91 that the sulfuric acid salt of nickel is the mainly electroless. Select the appropriate process, chemical nickel plating for experimental material, macro-or micro-morphology of electroless nickel deposits, measuring the hardness of nickel-plated, testing chemical corrosion resistance of nickel plating. Experiments show, we can generated plating layer on the surface of the AZ91 alloy with this technology, and the surface of the plating is the cell structure and there are more grain boundaries and defects on the cell surface ,the sulfuric processed chemical nickel plating layer is good to improve the magnesium alloy corrosion resistance, and the hardness is improved. Keywords: AZ91D magnesium alloy electroless nickel plating corrosive hardness t
钢的化学镀镍磷
钢的化学镀镍磷 DC 金属3090****** 材料科学与工程学院 摘要：本文简要介绍了钢铁化学镀镍磷的原理与工艺流程，简述了镀层的性能及技术指标，随之分析了影响镀层性能的主要因素，并据此给出了工艺中的除锈配方和镀液配方，最后对试验参数进行了测定与比较，得出了一定的结论，由此论证了化学镀镍磷的重要作用和这一工艺对钢铁性能改进的重要影响。 关键词：原子氢态理论镀层工艺热处理参数测定 前言：化学镀镍磷工艺是近年来迅速发展起来的一种新型表面保护和表面强化技术手段，具有广泛的应用前景。目前化学镀镍磷合金已广泛地应用在石油化工、石油炼制、电子能源、汽车、化工等行业。石油炼制和石油化工是其最大的市场，并且随着人们对这一化学镀特性的认识，它的应用也越来越广泛，主要用在石油炼制、石油化工的冷换设备上，化学镀镍磷能够显著提高设备的耐磨、耐蚀性能，延长其寿命，性能优于目前使用的有机涂料，而且适用于碳钢、铸铁、有色金属等不同基材[1]。 一、实验原理 化学镀镍磷合金是一种在不加电流的情况下，利用还原剂在活化零件表面上自催化还原沉积得到镍磷镀层的方法。其主要反应为应用次亚磷酸钠还原镍离子为金属镍，即在水溶液中镍离子和次亚磷酸根离子碰撞时，由于镍触媒作用析出原子态氢，而原子态氢又被催化金属吸附并使之活化，把水溶液中的镍离子还原为金属镍形成镀层，另外次亚磷酸根离子由于在催化表面析出原子态氢的作用，被还原成活性磷，与镍结合形成Ni-P合金镀层。 以次磷酸钠为还原剂的化学镀镍磷工艺，其反应机理，现普遍被接受的是“原子氢态理论”和“氢化物理论”。下面介绍“原子氢态理论”，其过程可分为以下四步： 1、化学沉积镍磷合金镀液加热时不起反应，而是通过金属的催化作用，次亚磷酸根在水溶液中脱氢而形成亚磷酸根，同时放出初生态原子氢。 H2PO2-+H2O→HPO3-+2H+H-
化学镀镍配方汇编
简述电镀槽液加料方法与溶液密度测定方法 1.电镀生产现场工艺管理的主要内容： 1)控制各槽液成分在工艺配方规范内。遵守规定的化学分析周期。 2)保持电镀生产的工艺条件。如温度、电流密度等。 3)保持阴极与阳极电接触良好。 4)严格的阴极与阳极悬挂位置。 5)保持镀液的清洁和控制镀液杂质。 6)保持电镀挂具的完好和挂钩、挂齿良好的电接触。 2.电镀槽液加料方法：加料要以“勤加”“少加”为原则。 2.1固体物料的补充，某些有机固体料先用有机溶剂溶解,再慢慢加入以提高增溶性。若直接加入往往会使镀液混浊。一般的固体物料,可用镀槽中的溶液来分批溶解。即取部分电镀液把要加的料在搅拌下慢慢加入,待静止澄清,把上层清液加入镀槽。未溶解的部分,再加入镀液,搅拌溶解。这样反复作业,直到全部加完。在不影响镀液总体积的情况下,也可以用去离子水或热的去离子水搅拌溶解后加入镀槽。有些固体料易形成团状,影响溶解过程。可以先用少量水调成稀浆糊状,逐步冲稀以避免团状物的形成。 2.2液体物料的补充，可以用去离子水适当稀释或用镀液稀释后在搅拌下慢慢加入。严禁将添加剂光亮剂的原液加入镀槽。 2.3补充料的时机，加料最好是在停镀时进行。加入后经过充分搅匀再投入生产。在生产中加料,要在工件刚出槽后的“暂休”时段加入。可在
循环泵的出液口一方加入,加入速度要慢,药料随着出液口的冲击力很快分散开来。 2.4加料方法不当可能造成的后果： 2.4 1)如果加入的是光亮剂,则易造成此槽工件色泽差异。 2.4.2)如果加入的是没有溶解的固体料,则易造成镀层毛刺或粗糙。 2.4.3)如果是加入酸调节pH,会造成槽液内部pH不均匀而局部造成针孔。 3.镀液及其它辅助溶液密度的测试方法： 3.1要经常测定溶液的密度，新配制的镀液或其它辅助液,都要测定它的密度并作为档案保存起来供以后对比。镀液的密度一般随着槽龄增加而增加。这是由于镀液中杂质离子、添加剂分解产物等积累的结果,因此可以把溶液密度与溶液成分化验数据一起综合进行分析,判断槽液故障原因以利排除。 3.2溶液密度测定方法，在电镀生产中,常用密度计或波美计测试溶液密度。密度与波美度可以通过下列公式转换。对重于水的液体密度 =145/(145-波美度),波美度=(145x145)/密度,在用波美计测试时,其量程要从小开始试测,若波美计量程选择不当,会损坏波美计。 测试密度不要在镀槽内进行,应取出部分镀液在槽外进行。在镀槽中测试,当比重计或波美计万一损坏,镀液会被铅粒污染。应将待测液取出1.5L左右(用2000mL烧杯),热的溶液可用水浴冷却。然后将样液转移至1000mL直形量筒中,装入量为距筒口约20mm处,就可用比重计测量。 脉冲电镀电源使用须知
镁合金防腐蚀方案汇总
镁合金防腐蚀方案汇总 化学转化处理 镁合金的化学转化膜按溶液可分为：铬酸盐系、有机酸系、磷酸盐系、KMnO4系、稀土元素系和锡酸盐系等。 传统的铬酸盐膜以Cr为骨架的结构很致密，含结构水的Cr则具有很好的自修复功能，耐蚀性很强。但Cr具有较大的毒性，废水处理成本较高，开发无铬转化处理势在必行。镁合金在KMnO4溶液中处理可得到无定型组织的化学转化膜，耐蚀性与铬酸盐膜相当。碱性锡酸盐的化学转化处理可作为镁合金化学镀镍的前处理，取代传统的含Cr、F或CN等有害离子的工艺。化学转化膜多孔的结构在镀前的活化中表现出很好的吸附性，并能改镀镍层的结合力与耐蚀性。 有机酸系处理所获得的转化膜能同时具备腐蚀保护和光学、电子学等综合性能，在化学转化处理的新发展中占有很重要的地位。 化学转化膜较薄、软，防护能力弱，一般只用作装饰或防护层中间层。 阳极氧化 阳极氧化可得到比化学转化更好的耐磨损、耐腐蚀的涂料基底涂层，并兼有良好的结合力、电绝缘性和耐热冲击等性能，是镁合金常用的表面处理技术之一。 传统镁合金阳极氧化的电解液一般都含铬、氟、磷等元素，不仅污染环境，也损害人类健康。近年来研究开发的环保型工艺所获得的氧化膜耐腐蚀等性能较经典工艺Dow17和HAE有大程度的提高。优良
的耐蚀性来源于阳极氧化后Al、Si等元素在其表面均匀分布，使形成的氧化膜有很好的致密性和完整性。 一般认为氧化膜中存在的孔隙是影响镁合金耐蚀性能的主要因素。研究发现通过向阳极氧化溶液中加入适量的硅-铝溶胶成分，一定程度上能改善氧化膜层厚度、致密度，降低孔隙率。而且溶胶成分会使成膜速度出现阶段性快速和缓慢增长，但基本上不影响膜层的X 射线衍射相结构。 但阳极氧化膜的脆性较大、多孔，在复杂工件上难以得到均匀的氧化膜层。 金属涂层 镁及镁合金是最难镀的金属，其原因如下： (1)镁合金表面极易形成的氧化镁，不易清除干净，严重影响镀层结合力; (2)镁的电化学活性太高，所有酸性镀液都会造成镁基体的迅速腐蚀，或与其它金属离子的置换反应十分强烈，置换后的镀层结合十分松散; (3)第二相(如稀土相、γ相等)具有不同的电化学特性，可能导致沉积不均匀; (4)镀层标准电位远高于镁合金基体，任何一处通孔都会增大腐蚀电流，引起严重的电化学腐蚀，而镁的电极电位很负，施镀时造成针孔的析氢很难避免; (5)镁合金铸件的致密性都不是很高，表面存在杂质，可能成为
实验15_光亮镀锌及化学镀镍实验报告
5.3数据处理 (1)电镀锌的电流密度：J=I/S=0.8A/(3.5cm×3.5cm×2)=0.0326A/cm2 (2)碱性光亮镀锌的电流效率： 实验中锌的实际析出量为: 第一次镀锌：113.5mg/(0.8A×10min×60s/min)=0.2364mg/C 第二次镀锌：111.0mg/(0.8A×10min×60s/min)=0.2312mg/C 锌的理论析出量为0.339 mg/C 则镀锌的电流效率为： 第一次镀锌：（0.2364 mg/C）/（0.339 mg/C）×100%=69.73% 第二次镀锌：（0.2312mg/C）/（0.339 mg/C）×100%=68.20% (3)质量法测得第一次镀锌的镀层厚度： [0.1135g/(7.17g/cm3)/(3.5cm×3.5cm)]/2=6.461×10-4cm 质量法测得第二次镀锌的镀层厚度： [0.1110g/(7.17g/cm3)/(3.5cm×3.5cm)]/2=6.319×10-4cm (4)镍磷合金镀层的厚度：(0.0403g/(8.30g/ cm3))/( 3.5cm×3.5cm)=3.964×10-4cm 化学镀镍的沉积速度：3.964um/(20min×1/60h/min)=11.892um/h (5) 孔隙率：41/(3.3cm×3.3cm) = 3.76个/cm2 (6)评价两种镀层的外观：用镀锌法镀后得到的铁片表面较光滑和有光泽，而且镀层较厚，但均匀度不够高；用化学镀镍法得到的铁片表面光滑，镀层均匀，但光泽不及化学镀锌好，且镀层较薄。 6 讨论与分析 6.1本实验中镀锌用电流0.8A，因为反应速度较快能得到镀层比较好的铁片。 6.2由计算电流效率可知，本实验电流效率偏小，可能是因为电流较大，搅拌速度较快使得镀层较难附着在铁片上。 6.3计算的孔隙率较小，滤纸上的斑点都是较小的，几乎没有连起来的斑点，可能是因为小气泡，以及预处理不够到位，或者含有其他杂质造成的。 6.4本次实验需要对铁片进行退锌、除灰、除油的预处理，这是实验成功的关键，实验时应尽量避免用手触碰而使其沾上油污，影响镀层质量。 6.5本组比较两种方法发现，镀锌过程出泡不是很均匀，且有一侧有大量气泡，另一侧较少，因此均匀度不够好。而化学镀镍过程气泡均匀出现，因此镀层较均匀。
镁合金化学镀
论文 课程名称：轻金属表面处理技术班级： 学号： 姓名： 专业：应用化学 成绩：
镁合金化学镀技术研究进展 摘要综述了镁合金化学镀技术的研究历史和现状，重点介绍了镀前处理工序的革新、镀液配方的优化、多元镀以及复合镀技术的开发，在此基础上指出了镁合金化学镀技术今后的发展方向。 关键词镁合金化学镀表面改性 Abstract The development history of electroless planting on magnesium alloy is simply introduced and a review is made on the status of it.The research progress in the pretreatment,bath formula,polybasic and composite coating is focused.On the basic of them,the existing questions and development tendency of the electroless plating on magnesium alloy are indicated. Key words magnesium alloys,electroless plating,surface modification 1.引言 镁作为最轻的金属结构材料，具有密度低、比强度高、弹性模量小、尺寸稳定、易于回收等优势。随着镁加工工艺的改进，特别是环保标准的提高，镁合金逐渐成为继钢铁、铝之后的第三大金属结构材料，在汽车、航空航天、电子等领域有着广阔的应用前景，但是镁合金化学性质活泼，在侵蚀性环境中极易遭受腐蚀破坏，至今没有得到与其资源、性能相匹配的大规模的工业应用，因此，表面防护处理对于镁合金作为结构材料的应用具有十分重要的意义。目前镁合金的表面处理方法主要有化学镀、电镀、化学转化、阳极/微弧氧化、有机涂装等。其中化学镀技术以其设备投资少、不受工件尺寸和形状限制、镀层性能优越等优势日益受到关注。 常规金属的化学镀技术在20世纪40年代由A.Brenner和G.Riddell研制成功。经过几十年的努力，针对铁基、铝基等处理对象，现已解决诸如镀液再生、镀液稳定性、镀层组织结构性能测试等问题。化学镀技术已逐渐趋于成熟，并在航空航天、汽车、石化、机械、矿业、军事、3C等领域得到了广泛应用。 与铁基和铝基材料相比，镁合金属于难镀基材，其化学镀工艺更复杂、更困难。原因如下：①镁化学性质活泼，自氧化薄膜在合金表面迅速生成，妨碍了沉积金属与基底形成金属－金属键，影响镀层/基体的结合强度；②镁在普通镀液中与其它金属离子置换反应剧烈，容易导致沉积的镀层疏松、多孔、结合力差； ③镁合金的基体相和第二相有不同的电极电位，易形成腐蚀微电池，造成基体严重腐蚀，进而导致镀层沉积不均匀；④镁的标准电极电位低，镀层一般呈阴极性，
化学镀镍溶液的各种成分
化学镀镍溶液的各种成分 优异的化学镀镍溶液产生优异的化学镀镍层是必不可少的。化学镀镍溶液应包括：镍盐、还原剂、络合剂、缓冲剂、加速剂、稳定剂、光亮剂、润湿剂等。 主盐 化学镀镍溶液中的主盐就是镍盐，如硫酸镍、氯化镍、醋酸镍等，由它们提供化学镀反应过程中所需要 的镍离子。早期曾用过氯化镍做主盐，但由于氯离子的存在不仅会降低镀层的耐蚀性，还产生拉应力，所以目前已很少有人使用。同硫酸镍相比用醋酸镍做主盐对镀层性能是有益的。但因其价格昂贵而无人使用。其实最理想的镍离子来源应该是次磷酸镍，使用它不至于在镀浴中积存大量的硫酸根，也不至于在使用中随着补加次磷酸钠而带入大量钠离子，同样因其价格因素而不能被工业化应用。目前应用最多的就是硫酸镍，由于制造工艺稍有不同而有两种结晶水的硫酸镍。因为硫酸镍是主盐，用量大，在镀中还要进行不断的补加，所含杂质元素会在镀液的积累，造成镀液镀速下降、寿命缩短，还会影响到镀层性能，尤其是耐蚀性。所以在采购硫酸镍时应该力求供货方提供可靠的成分化验单，做到每个批量的质量稳定，尤其要注意对镀液有害的杂质尤其是重金属元素的控制。 还原剂 用得最多的还原剂是次磷酸钠，原因在于它的价格低、镀液容易控制，而且合金镀层性能良好。次磷酸钠在水中易于溶解，水溶液的PH值为6。是白磷溶于NaOH中，加热而得到的产物。目前国内的次磷酸钠制造水平很高，除了国内需求外还大量出口。 络合剂 化学镀镍溶液中除了主盐与还原剂以外，最重要的组成部分就是络合剂。镀液性能的差异、寿命长短主要取决于络合剂的选用及其搭配关系。 络合剂的第一个作用就是防止镀液析出沉淀，增加镀液稳定性并延长使用寿命。如果镀液中没有络合剂存在，由于镍的氢氧化物溶解度较小，在酸性镀液中便可析出浅绿色絮状含水氢氧化镍沉淀。硫酸镍溶于水后形成六水合镍离子，它有水解倾向，水解后呈酸性，这时即析出了氢氧化物沉淀。如果六水合镍离子中有部分络合剂存在则可以明显提高其抗水解能力，甚至有可能在碱性环境中以镍离子形式存在。不过，pH 值增加，六水合镍离子中的水分子会被OH根取代，促使水解加剧，要完全抑制水解反应，镍离子必须全部螯合以得到抑制水解的最大稳定性。镀液中还有较多次磷酸根离子存大，但由于次磷酸镍溶液度较大，一般不致析出沉淀。镀液使用后期，溶液中亚磷酸根聚集，浓度增大，容易析出白色的NiHPO3.6H2O沉淀。加入络合剂以后溶液中游离镍离子浓度大幅度降低，可以抑制镀液后期亚磷酸镍沉淀的析出。络合剂的第二个作用就是提高沉积速度，加络合剂后沉积速度增加的数据很多。加入络合剂使镀液中游离镍离子浓度大幅度下降，从质量作用定律看降低反应物浓度反而提高了反应速度是不可能的，所以这个问题只能从动力学角度来解释。简单的说法是有机添加剂吸附在工件表面后，提高了它的活性，为次磷酸根释放活性原子氢提供更多的激活能，从而增加了沉积反应速度。络合剂在此也起了加速剂的作用。 能应用于化学镀镍中的络合剂很多，但在化学镀镍溶液中所用的络合剂则要求它们具有较大的溶解度，存在一定的反应活性，价格因素也不容忽视。目前，常用的络合剂主要是一些脂肪族羧酸及其取代衍生物，如丁二酸、柠檬酸、乳酸、苹果酸及甘氨酸等，或用它们的盐类。在碱浴中则用焦磷酸盐、柠檬酸盐及铵盐。不饱和脂肪酸很少使用，因不饱和烃在饱和时要吸收氢原子，降低还原剂的利用率。而常见的一元羧酸如甲酸、乙酸等则很少使用，乙酸常用作缓冲剂，丙酸则用作加速剂。 稳定剂 化学镀镍溶液是一个热力学不稳定体系，由于种种原因，如局部过热、pH值提高，或某些杂质影响，不可避免的会在镀液中出现一些活性微粒—催化核心，使镀液发生激烈的均向自催化反应，产生大量Ni—P
低磷化学镍配方与超低磷化学镀镍工艺
超低磷化学镍配方与低磷化学镀镍工艺 （周生电镀导师） 超低磷化学镍工艺，主要应用于低温有稳定的镀速，它可以在连续补充的情况下有很长的使用寿命。镀层的性能光滑，低应力和含有3-6%的磷。超低磷配方可保持2%左右的磷含量。镀层硬度为530-580HV，增加钴含量则硬度可以超过700HV，每小时的沉积速度为6-8μm。 NI-1166含有三种成份， NI-1166A和 NI-1166B用作配缸， NI-1166A和NI-1166C用作补充。 周生电镀导师之（@q）：（3）（8）（0）（6）（8）（5）（5）（0）（9） 电镀导师之[（微）（Xin）]：（1）（3）（6）（5）（7）（2）（0）（1）（4）（7）（0） ●配方平台不断发展完善 我们的配方平台包含的成熟量产商业配方，已有AN美特、乐思、罗哈、麦德美、国内知名公司配方。 配方平台帮助了很多中小企业提高产品技术水平，也有不少个人因此创业成功，帮助国内企业抢占国外知名企业市场，提升国产占有率是我们长期追求的目标。 ●说明 目前市场上有很多类似抄袭或者是买过部分配方后再次转卖的，他们会改动数据，而且不会有后期的改进和升级。他们甚至建立Q群或者微@信群推销配方。我们没有建立任何群。一切建&群的都是假冒。（本*公*告*长*期*有*效）。有些号称配方公开的公司，其实公开的是代号配方，靠高价卖代号原料赚取高额利润，希望买配方的用户不要被此类广*告忽悠。
●配缸方法 1.用去离子水清洗镀槽。 2.加入部份去离子水。 3.添加所需量的 NI-1166A和 NI-1166B搅拌均匀，然后加水至工作液位。 4.加热溶液至操作温度，检测PH值是否标准。 ●补充 为了维护最佳的电镀速率，应通过分析镍的方法，将其控制在5.2-6.0g/L。 1.金属镍 在操作中，可以通过补充 NI-1166A和 NI-1166C来补充金属镍和还原剂。每补充1g金属镍需要添加10ml/L的 NI-1166A和20ml/L的 NI-1166C。 2. 还原剂 还原剂的范围是20-40g/L,在正常的不需要额外添加 NI-1166C。
化学镀镍(无解电镀镍介绍)
化学镀镍介绍 化学镀镍的定义与分类 化学镀镍，又称为无电解镀镍，是在金属盐和还原剂共同存在的溶液中靠自催化的化学反应而在金属表面沉积了金属镀层的新的成膜技术。 化学镀镍所镀出的镀层为镍磷合金，按其磷含量的不同可分为低磷、中磷、高磷三大类，磷含量低于3%的称为低磷，磷含量在3-10%的为中磷，高于10%的为高磷，其中中磷的跨度比较大，一般我们常见的中磷镀层为6-9%的磷含量。 当然，本站主要介绍的是化学镀镍磷合金，有时为了方便我们简称化学镀了，而且EN也是化学镀镍简称。但化学镀不仅此一种镀种，比较成熟的还有化学镀铜，化学镀金，化学镀锡，还有一种复合镀层。其它镀种的市场占有量不足总量的1%，本站不做重点介绍。 化学镀镍的特点与发展简史 化学镀镍的历史与电镀相比，比较短暂，在国外其真正应用到工业仅仅是70年代末80年代初的事。 1844年，Wurtz发现金属镍可以从金属镍盐的水溶液中被次磷酸盐还原而沉积出来。经过了很多年1911年Bretau等研究者发表了有关次磷酸盐对镍盐的还原反应的研究的报告。但那时的化学镀镍溶液极不稳定，自分解严重，只能得到黑色粉末状镍沉积物或镍镜附着物镀层，没有实际价值。 化学镀镍技术的真正发现并使它应用至今是在1944年，美国国家标准局的 A.Brenner和G.Riddell的发现，他们发现了克服沉积出粉末状镍的配方，于1946年和1947年两年中发表了很有价值的研究报告。 化学镀镍工艺的庆用比实验室研究成果晚了近十年。第二次世界大战以后，美国通用运输公司对这种工艺发生了兴趣，他们想在运输烧碱筒的内表面镀镍，而普通的电镀方法无法实现，五年后他们研究了发展了化学镀镍磷合金的技术公布了许多专利。1955年造成了他们的第一条试验生产线，并制成了商业性有用的化学镀镍溶液，这种化学镀镍溶液的商业名称为“Kanigen”。 目前在国外，特别是美国、日本、德国化学镀镍已经成为十分成熟的高新技术在各个工业部门得到了广泛的应用。 （国内的化学镀镍发展也十分迅速，据第五届化学镀年会发表文章的统计就已经有300多家厂家，但这一数字在当时也是极为保守的。据站长推测国内目前每年的化学镀镍浓缩液消耗量在10万吨左右，总市场规模在150亿左右。） 化学镀镍溶液的组成与镀液成分设计常识 优异的镀液配方对于产生最优质的化学镀镍层是必不可少的。化学镀镍溶液应包括：镍盐、还原剂、络合剂、缓冲剂、促进剂、稳定剂、光亮剂、润湿剂等。 主盐 化学镀镍溶液中的主盐就是镍盐，如硫酸镍、氯化镍、醋酸镍等，由它们提供化学镀反应过程中所需要的镍离了。早期曾用过氯化镍做主盐，由于氯离子的存在不仅会降低镀层的耐蚀性，还产生拉应力，所以目前已不再使用。同硫酸镍相比用醋酸镍做主盐对镀层性能的有益贡献因其价格昂贵而被抵消。其实最理想的镍离子来源应该是次磷酸镍，使用它不至于在镀浴中积存大量的硫酸根，也不至于使用中被加次磷酸钠而大量带入钠离子，同样因其价格因素而不能被工业化应用。目前应用最多的就是硫酸镍，由于制造工艺稍有不同而有两种结晶水的硫酸镍。因为硫酸镍是主盐，用量大，在镀中还要进行不断的补加，所含杂质元素会在镀液的积累，造成镀液镀速下降、寿命缩短，还会影响到镀层性能，尤其是耐蚀性。所以在采购硫酸镍时应该力求供货方提供可靠的成分化验单，做到每个批量的质量稳定，尤
表面工程综合实验预实验报告
表面综合实验论文 目录 碳钢的化学镀NI-P (3) 第一章实验机理 (3) 第二章工艺流程 (4) 第三章关键工艺目的及溶液参数 (4) 3.1准备试样 (4) 3.2碱性除油 (5) 3.2.1除油目的： (5) 3.2.2除油溶液参数： (5) 3.3酸洗（除锈+活化） (5) 3.4化学镀 (5) 3.4.1化学镀成分及作用 (5) 3.4.2化学镀溶液参数 (6) 3.5镀后热处理 (6) 第四章检测与分析 (7) 4.1表面形貌分析 (7) 4.2镀层厚度测定 (7) 4.3镀层及镀后热处理硬度测定 (7) 4.4镀后耐蚀性检测 (8) 参考文献： (8) 钢的磷化 (10) 第一章实验机理 (10) 1.1磷化膜的形成机理 (10) 1.2磷化膜的组成和结构 (11) 第二章工艺流程 (12) 1
第三章关键工艺目的及溶液参数 (12) 3.1准备试样 (12) 3.2碱性除油 (12) 3.2.1除油目的 (12) 3.2.2除油溶液参数 (12) 3.3酸洗（除锈+活化） (13) 3.4磷化 (13) 3.4.1高温磷化的磷酸盐溶液参数 (13) 3.5磷化膜的后处理 (13) 第四章检测与分析 (14) 4.1表面形貌分析 (14) 4.2磷化膜厚度测定 (14) 4.3磷化后硬度测定 (14) 4.4磷化后耐蚀性检测 (14) 参考文献： (15)
碳钢的化学镀Ni-P 学院名称：材料科学与工程学院专业班级：金属1501 学生姓名：高奇指导教师：王云龙王兰 摘要：本文简要介绍了碳钢化学镀镍磷的原理与工艺流程，根据实验结果和实验过程中出现的一些问题，阐述了化学镀镍磷的基本知识，论证了化学镀镍磷的重要作用，得出了这一工艺对碳钢性能改进的重要影响。 关键词：原子氢态理论配方溶液参数检测分析 第一章实验机理 化学镀镍磷合金是一种在不加电流的情况下，利用还原剂在活化零件表面上自催化还原沉积得到镍磷镀层的方法。其主要反应为应用次亚磷酸钠还原镍离子为金属镍，即在水溶液中镍离子和次亚磷酸根离子碰撞时，由于镍触媒作用析出原子态氢，而原子态氢又被催化金属吸附并使之活化，把水溶液中的镍离子还原为金属镍形成镀层，另外次亚磷酸根离子由于在催化表面析出原子态氢的作用，被还原成活性磷，与镍结合形成Ni-P合金镀层。 以次磷酸钠为还原剂的化学镀镍磷工艺，其反应机理，现普遍被接受的是“原子氢态理论”和“氢化物理论”。下面介绍其中一种“原子氢态理论”，其过程可分为以下四步： （1）化学沉积镍磷合金镀液加热时不起反应，而是通过金属的催化作用，次亚磷酸根在水溶液中脱氢而形成亚磷酸根，同时放出初生态原子氢。 H2PO2-+H2O→HPO3-+2H+H- （2）初生态原子氢被吸附在催化金属表面上而使其活化，使镀液中的镍阳离子还原，在催化金属表面上沉积金属镍。 Ni2++2H→Ni+2H+