1、Designation: B 904 00 (Reapproved 2004)Standard Specification forAutocatalytic Nickel over Autocatalytic Copper forElectromagnetic Interference Shielding1This standard is issued under the fixed designation B 904; the number immediately following the designation indicates the year oforiginal adoption
2、 or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. ScopeThis specification presents the requirements for multilayercoatings of autocata
3、lytic nickel-phosphorus over autocatalyticcopper on metallic and polymeric substrates. The coatingsystem is intended to provide electromagnetic interference(EMI) protection properties or electrostatic discharge (ESD)protection to parts fabricated from either polymeric or metallicmaterials.2. Referen
4、ced Documents2.1 ASTM Standards:2A 919 Terminology Relating to Heat Treatment of Metals3B 183 Practice for Preparation of Low-Carbon Steel forElectroplatingB 242 Practice for Preparation of High-Carbon Steel forElectroplatingB 252 Guide for Preparation of Zinc Alloy Die Castings forElectroplating an
5、d Conversion CoatingsB 253 Guide for Preparation of Aluminum Alloys for Elec-troplatingB 320 Practice for Preparation of Iron Castings for Electro-platingB 322 Practice for Cleaning Metals Prior to ElectroplatingB 374 Terminology Related to ElectroplatingB 504 Test Method for Measurement of Thicknes
6、s of Me-tallic Coatings by the Coulometric MethodB 532 Specification for the Appearance of ElectroplatedPlastic SurfacesB 533 Test Method for Peel Strength of Metal ElectroplatedPlasticsB 553 Test Method for Thermal Cycling of ElectroplatedPlasticsB 554 Practice for Measurement of Thickness of Metal
7、licCoatings on Nonmetallic Substrates3B 567 Test Method for Measurement of Coating Thicknessby the Beta Backscatter MethodB 568 Test Method for Measurement of Coating Thicknessby X-Ray SpectrometryB 602 Test Method for Attribute Sampling of Metallic andInorganic CoatingsB 697 Guide for Selection of
8、Sampling Plans for Inspectionof Electrodeposited Metallic and Inorganic CoatingsB 727 Practice for Preparation of Plastics Materials forElectroplatingB 733 Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on MetalD 3330/D 3330M Test Method for Peel Adhesion ofPressure-Sensiti
9、ve TapeD 3359 Test Methods for Measuring Adhesion by Tape TestD 4935 Test Method for Measuring the ElectromagneticShielding Effectiveness of Planar Materials2.2 Military Standard:MIL-STD-461 Electromagnetic Emission and Susceptibil-ity Requirements for the Control of ElectromagneticInterference43. T
10、erminology3.1 DefinitionsMany of the terms used in this specifica-tion can be found in Terminologies A 919 or B 374.3.2 Definitions of Terms Specific to This Standard:3.2.1 significant surfaces, nthese surfaces are classified asprimary, secondary, nonsignificant, and coating-free surfaces.3.2.1.1 co
11、ating-free areas, adjareas specified on partdrawings or suitably marked samples.3.2.1.2 nonsignificant surfaces, adjall holes, recesses, andother areas where a controlled deposit cannot be obtainedunder normal coating conditions and that cannot be touchedwith a 20-mm diameter ball shall be considere
12、d nonsignificantsurfaces unless otherwise specified on part drawings or suitablymarked samples.3.2.1.3 primary significant surface, adjall mating sur-faces and those other surfaces specified on part drawings orsuitably marked samples.1This specification is under the jurisdiction of ASTM Committee B0
13、8 onMetallic and Inorganic Coatings and is the direct responsibility of SubcommitteeB08.08.01 on Engineering Coatings.Current edition approved Oct. 1, 2004. Published October 2004. Originallyapproved in 2000. Last previous edition approved in 2000 as B 904 00.2For referenced ASTM standards, visit th
14、e ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700Robbins Ave. P
15、hiladelphia, PA 191115094, Attn: NPODS.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.3.2.1.4 secondary significant surfaces, adjall surfaces,other than primary significant surfaces, that can be touchedwith a 20-mm diameter ball sha
16、ll be considered secondarysignificant surfaces unless otherwise specified on part drawingsor suitably marked samples.4. Classification4.1 This classification system provides for the following:4.1.1 Types of coating based on thickness and testingrequirements, and4.1.2 Grades of coating based on alloy
17、 composition.4.2 Coating Type:4.2.1 The coating type indicates the type of application andtests to be used in determining the acceptance of the coating.4.2.2 Coating Type Definitions:4.2.2.1 Type 1Coatings intended to shield devices forFCC/VDE Class B service.4.2.2.2 Type 2Coatings intended to shiel
18、d devices forFCC/VDE Class B service in harsh environments.4.2.2.3 Type 3Coatings intended to shield devices forMIL-STD-461 requirements.4.2.2.4 Type 4Coatings intended to shield devices forFCC/VDE Class A requirements.4.2.3 The description of Types 1, 2, 3, and 4 is summarizedin Table 1.4.3 Coating
19、 Grade:4.3.1 The coating grade is based upon phosphorus content.NOTE 1The coating grade indicates the relative contact impedanceand the relative corrosion resistance of the nickel-phosphorus coating andtests to be used in determining the acceptance of the coating4.3.2 Coating Grade Definitions:4.3.3
20、 Grade 1 coatings have a phosphorus content between3 and 5 %.NOTE 2Low phosphorus coatings exhibit low electrical contact im-pedance. High phosphorus contents exhibit somewhat higher contactimpedance, however, the coating is more corrosion resistant.4.3.4 Grade 2 coatings have a phosphorus content b
21、etween6 and 11 %.NOTE 3The adhesion and resistance to blistering are improved onsome polymeric substrates by an initial flash deposit of autocatalyticnickel.5. Ordering Information5.1 To avoid misunderstanding between contractual parties,purchase orders or contracts for autocatalytic nickel overauto
22、catalytic copper coatings under this specification shouldinclude the designation, issue date, and the following informa-tion:5.1.1 Type of substrate.5.1.1.1 Metallic substrates should state the composition andmetallurgical condition. Assemblies of dissimilar materialsshould be identified.5.1.1.2 Pol
23、ymeric substrates should state the polymer typeand should be of a plating grade.5.1.2 Classification of the deposit by type and grade.5.1.3 Primary significant surfaces and coating-free surfacesmust be indicated on drawings.5.1.4 Any special requirements.5.1.5 Test methods for coating adhesion, thic
24、kness, porosity.5.1.6 Sampling program.6. Surface Preparation6.1 Surface ContaminationSurfaces of polymeric partsmust be free of all mold release agents, dirt, oil, grease, andcontamination detrimental to the final finish. Surfaces ofmetallic parts must be free of all scale, oxidation, and contami-n
25、ation detrimental to the final finish. A clean surface isessential to the adhesion and electrical conductivity require-ments of the subsequent coated part.6.2 Cleaning, Conditioning, and ActivatingAny adequatemethod of cleaning, conditioning, and activating is acceptableprovided the coated parts mee
26、t the inspection requirements andare free of distortion. Examples of adequate methods ofcleaning can be found in 10.2.6.2.1 Base Material SuitabilityThe parts to be coatedshall be inspected by the coater prior to any processing todetermine their suitability for coating. Unsuitable parts shall beretu
27、rned to the fabricator or molder.6.3 Mechanical RougheningMechanical roughening ofpolymer surfaces, to promote adhesion, may only be used whenspecified on the part drawing.7. In-Process Storage and Handling7.1 Following cleaning, conditioning, and activating, allparts shall be immediately coated wit
28、h copper and thennickel-phosphorus to the thickness specified in Table 1. Theparts processing cycle shall be a continuous operation withoutany interruption.7.2 HandlingThe parts shall be suitably racked so as toprevent gas entrapment and to avoid physical handling of theprimary significant surfaces.
29、7.3 DryingFollowing coating, the parts may be dried withwarm air currents. Drying temperature shall not exceed theheat distortion temperature of the substrate. Wetting agentsmay be used to enhance water shedding provided they do notinterfere with subsequent paint adhesion.7.4 StorageFollowing drying
30、, all parts shall be stored in aclean dry area, protected from corrosive fumes and humidityprior to packaging and shipment.TABLE 1 Autocatalytic Nickel-Phosphorus Over AutocatalyticCopper Coating Descriptions SummaryType Thickness ShieldingEffectiveness(Typical) inaccordance withTest MethodD 4935App
31、licationAutocatalyticCopperAutocatalyticNickel-Phosphorus1 1 m min 0.25 m min 80-100 dB FCC/VDEClass B2 1 m min 1.5 m min 80-100 dB HarshEnvironment3 2.5 m min 0.25 m min 90-110 dB MIL-STD-461B4 Optional/Notrequired1.0 m min 50-70 dB FCC/VDEClass AB 904 00 (2004)28. Inspection8.1 Process Qualificati
32、onAll nickel-phosphorus overcopper coatings shall be produced from processes qualified inaccordance with the requirements in Section 9.8.2 Nickel-Phosphorus Over Copper CoatingThe nickel-phosphorus coating shall meet the requirements of Specifica-tion B 733.8.2.1 AppearanceThe nickel-phosphorus over
33、 coppercoating shall be smooth, semi-bright, adherent, and free fromdefects that will impair the corrosion resistance, electricalconductivity or electromagnetic shielding effectiveness prop-erties of the coating, see Specification B 532 for polymericparts and Specification B 733 for metallic parts.8
34、.2.2 Blisters and Unplated Areas8.2.2.1 BlistersThe parts shall be examined visually for10 to 15 s or as necessary to adequately examine the entireplated surface at a distance of 600 to 900 mm (arms length) forevidence of blisters. Visually means 20/20 vision or correctedto 20/20. Parts exhibiting b
35、listers shall be rejected.8.2.2.2 Unplated AreasVoids, skips, and other unplatedareas, visible to the unaided eye, exposing the substrate shall belimited to the sizes and numbers shown in Table 2. Voids andskips exposing copper are not permitted.8.2.3 ThicknessThe thickness test shall be performed o
36、nthe primary and secondary significant surfaces of the finishedpart. Thickness shall be as specified in Table 1. For partsacceptance the combined thickness of deposit and tolerancespecified in Table 1 may be used, provided representative partsalso meet the electrical conductivity requirements specif
37、ied in8.2.5. The thickness of deposit on nonsignificant surfaces shallbe that which results from control on the primary and second-ary significant surfaces, provided plating coverage occurs,unless otherwise specified on the part drawing.8.2.3.1 Thickness Test MethodsThe following test meth-ods are s
38、uitable for measuring local thickness of nickel-phosphorus and copper coating, see Practice B 554. See 8.2.3.2for restrictions.Coulometric MethodSee Test Method B 504X-Ray MethodSee Test Method B 568Beta Backscatter MethodSee Test Method B 567(1) Coulometric MethodThis semi-destructive method issuit
39、able for the measurement of individual layers in the rangeof 0.25 to 100 m.(2) X-Ray MethodThis nondestructive method is suitablefor the measurement of individual layers in the range of 0.25 to65 m and shall be the referee method.(3) Beta Backscatter MethodThis nondestructive methodis suitable for m
40、easuring total coating thickness between 0.1and 100 m.8.2.3.2 RestrictionElectronic thickness testers utilizingthe Eddy-current principle are not suitable for this specificationand shall not be used.8.2.4 AdhesionThe coatings shall not peel or separatefrom the base material when subjected to the tap
41、e test (see9.4.1).8.2.5 Electrical ContinuityThe coating shall form a con-tinuous electrical path across the significant and nonsignificantsurfaces.8.2.5.1 Electrical CriteriaThe DC resistance of the coat-ing system, between all points of the primary significantsurfaces shall not exceed 0.1 V unless
42、 otherwise specified onpart drawings. The measurement shall be made with anohmmeter, having a sensitivity of at least 20 000 V/V, and ameasuring voltage of 9 6 3 V DC and a 2 A load.8.2.5.2 Electrical Measurement ProcedureThe DC resis-tance of the coating system, shall be measured on a test samplepr
43、epared by assembling two coated parts together, clampingthem with 2 M4, class 4.8 threaded fasteners assembled withtwo flat washers and a mating nut torqued to 1.52.0 NM. Themeasuring probes shall each be pressed firmly into the oppos-ing faces of the assembly so as to make intimate contact withthe
44、coating. Alternatively, when it is not practical to assembletwo parts together for this test, a single part may be used. Inthat event, press one probe firmly into the surface of the part sothat it is in intimate contact with the coating. The second probeshall be held in contact with the part surface
45、, in a position andwith a pressure approximating that of writing with a pencil.This probe shall have a radius of 1 mm minimum. The probesshall be held at least 25 and no more than 200 mm apart.8.3 SamplingA suitable sampling plan may be selectedfrom those in Test Method B 602. Guidance in selecting
46、asuitable sampling plan will be found in Guide B 697.9. Requirements for Process Qualification9.1 Process SelectionCommercial processes are availablethat meet the requirements of this specification.9.2 Coating CompositionThe composition of the nickel-phosphorus coating shall be 3 to 11 % phosphorus
47、and theremainder nickel. The composition of the copper coating shallbe 99 % copper minimum.9.3 Electrical IntegrityParts or coupons shall be subjectto 20 cycles of the cyclic temperature-humidity test and then tothe requirements of 8.2.5.1 and 8.2.5.2.9.4 AdhesionThe coatings shall not peel or separ
48、ate fromthe base material when subjected to the following tests.9.4.1 Tape Test:9.4.1.1 Apply a piece of pressure sensitive filament tape,approximately 25 mm wide and 75 mm long, onto the coatedsurface, pressing it firmly into place. Remove the tape, within5 minutes, with a continuous, smooth and ra
49、pid pull at an angleof approximately 90.9.4.2 The filament tape shall be 25 6 1 mm wide semitrans-parent pressure-sensitive tape with an adhesion strength of44.66 2.8 g/mm width when tested in accordance with TestMethods D 3330/D 3330M. The adhesion shall not changemore than 6 6.5 % of its mean value within 12 months.9.4.2.1 Pass/Fail CriteriaRemoval of any metal coatingshall constitute test failure.9.4.3 Adhesion-Cross HatchA series of six parallel cutsapproximately 25 mm long and 3 mm apart are made throughthe coating by mea
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