1、Designation: B481 68 (Reapproved 2013)Standard Practice forPreparation of Titanium and Titanium Alloysfor Electroplating1This standard is issued under the fixed designation B481; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.INTRODUCTIONFull utilization of the light weight and high strength of titanium is prevented by the tendency it hasto gall
3、and seize and by its lack of corrosion resistance at elevated temperatures. Frequently theselimitations can be overcome by electrodepositing upon the titanium a metal with satisfactoryproperties. Titanium is an active metal that rapidly forms an adherent oxide coating in the presence ofoxygen and wa
4、ter. This coating prevents the application of adherent electrodeposits by the morefamiliar preparative processes. For this reason, the special processes described in this practice weredeveloped.1. Scope1.1 This practice describes processes that have been foundto be successful in producing adherent e
5、lectrodeposits of goodquality on titanium and certain titanium alloys. Not all of theprocesses that have been reported as successful are described,but rather three basic ones that have had the widest use. Arather complete listing of the published work on electroplatingon titanium is given in the lis
6、t of references which appear at theend of this practice.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bilit
7、y of regulatory limitations prior to use. For a specifichazard statement, see 3.1.2. Referenced Documents2.1 ASTM Standards:2B343 Practice for Preparation of Nickel for Electroplatingwith Nickel3. Reagents3.1 Purity of ReagentsAll acids and chemicals used in thispractice are technical grade. Acid so
8、lutions are based upon thefollowing assay materials (WarningUse hydrofluoric acidwith extreme care.):Hydrochloric acid 37 mass %, density 1.184 g/mLHydrofluoric acid 60 mass %, density 1.235 g/mLHydrofluoric acid 71 mass %, density 1.260 g/mLHydrofluoric acid 100 mass %, density 1.0005 g/mLNitric ac
9、id 69 mass %, density 1.409 g/mL3.2 Purity of WaterUse ordinary industrial or potablewater for preparing solutions and rinsing.4. Process No. 14.1 CleaningRemove oil, grease, and other soil by appro-priate conventional processes such as vapor degreasing, alka-line cleaning, grinding, or blasting.4.2
10、 ActivatingActivation may be done by chemical orelectrochemical etching or liquid abrasive blasting. It is pos-sible that all three processes will work equally well on puretitanium and all common alloys; however, only those for whicheach process has been demonstrated to be successful are givenhere.
11、The suitability of a process for an alloy not listed shouldbe experimentally determined before committing productionparts.4.2.1 Chemical Etch:4.2.1.1 The following procedure is suitable for commer-cially pure titanium and for 6Al-4V, 4Al-4Mn, and 3Al-5Cr.4.2.1.2 PickleImmerse in the following soluti
12、on, at roomtemperature, until red fumes are evolved:1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.02 onPre Treatment.Current edition approved Dec. 1, 2013. Published December 2013. Originallyapprov
13、ed in 1968. Last previous edition approved in 2008 as B48168 (2008). DOI:10.1520/B0481-68R13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document
14、Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1HF (60 mass %) 1 volume andHNO3(69 mass %) 3 volumes4.2.1.3 Rinse.4.2.1.4 EtchImmerse in the following aqueous solutionfor 20 min (Note that a special for
15、mulation is recommended for3Al-5Cr alloy).Standard 3Al-5CrNa2Cr2O72H2O 250 g/L 390 g/LHF (60 % mass) 48 mL/L 25 mL/LTemperature 82 to 100C 82 to 100CNOTE 1For platinum electroplating on commercially pure titanium,etching may be done by immersion for 5 min in hot (94C min)concentrated hydrochloric ac
16、id followed by rinsing and platinum electro-plating (1)34.2.2 Rinse.4.2.3 ElectroplateElectroplate with chromium, with cop-per from an acid bath, or with nickel from either a Watts orsulfamate bath, or deposit nickel in an autocatalytic bath. If adeposit of some metal other than these three is desir
17、ed, firstapply a nickel coating with a minimum thickness of 1 mfollowed by the desired final metal.4.2.4 Heat Treat:4.2.4.1 The adhesion of the electrodeposit is mechanicaland, therefore, although of a relatively high order ofmagnitude, it may be less than adequate. If a higher degree ofadhesion is
18、desired, use nickel as an intermediate coating andheat treat. This causes interdiffusion of the nickel and titaniumand produces a metallurgical bond. The heat treatment can beperformed after all electroplating is applied or immediatelyafter the nickel electroplating. This later approach is used ince
19、rtain cases, for example, when undesirable diffusion canoccur between the nickel and the subsequent deposit.4.2.4.2 Heat treat in an inert gas atmosphere (for example,argon) for 1 to4hat540to800C. The exact time andtemperature should be selected by subjecting electroplated testpieces to adhesion or
20、performance tests or both.4.2.4.3 If the heat treatment is performed before applyingthe subsequent deposit, the nickel will have to be activatedbefore continuing the electroplating. Methods of activation aregiven in Practice B343.5. Process No. 25.1 CleanSee 4.1.5.2 Electrochemical Etch:5.2.1 The fo
21、llowing procedure is suitable for commerciallypure titanium and 4Al-4Mn alloy. The adhesion produced ispurely mechanical but sufficient to pass a bend test and heatingin a gas flame.5.2.2 PickleImmerse in the following solution at roomtemperature until red fumes are evolved:HF (60 mass %) 1 volume a
22、ndHNO3(69 mass %) 3 volumes5.2.3 Rinse.5.2.4 EtchImmerse in the following solution and makeanodic, raising the current above the operating value until localchemical attack of the metal is stopped as evidenced by thecessation of gassing. Then reduce the current to the operatingvalue and etch anodical
23、ly at 5.4 A/dm2for 15 to 30 min.HF (anhydrous) 15 mass %H2O 6 mass %Ethylene glycol 79 mass %Temperature 55 to 60C5.2.4.1 The formulation in 5.2.4 is equivalent to the follow-ing volumetric formulation.HF (71 mass %) 19 volumes andEthylene glycol 81 volumes5.2.4.2 The water content must not be too h
24、igh; therefore,less concentrated grades of hydrofluoric acid cannot be substi-tuted for the 71 % grade. The solution or part should be mildlyagitated. The cathodes may be carbon, nickel, copper, or othermaterials not attacked by the solution.5.2.4.3 Remove the part while the current is still on.5.2.
25、4.4 Excessive current densities will produce electropol-ishing and inadequate current densities will permit localchemical attack. Both conditions will result in lack of adhesionof the electroplating.5.2.5 Rinse.5.2.6 ElectroplateElectroplate with copper from an acidbath or copper from a cyanide bath
26、 preceded by a cyanidecopper strike, with cadmium from a cyanide bath, with silverfrom a cyanide bath, or with nickel from a Watts bath.6. Process No. 36.1 CleanSee 4.1.6.2 Liquid Abrasive Blasting:6.2.1 The following procedure is suitable for commerciallypure titanium, 3Al-5Cr, 5Al-2Cr-2Mo, 7Al-5Cr
27、, 2.5Al-16V,4Al-4Mn, 2Fe-2Cr-2Mo, 28Cr-1.5Fe, 6Al-4V, and 3Al-13V-11Cr.6.2.2 BlastingBlast all surfaces with a water-abrasiveslurry until a uniform appearance is achieved. The grit may beas coarse as 100 mesh or as fine as 1250. The finer grits requiresomewhat more time but do not cause roughening o
28、f thesurface or dimensional changes. The grit should be usedexclusively for blasting titanium to avoid imbedding of con-taminants such as iron that can cause local failures in thecoating.6.2.3 ElectroplatingDeposit nickel from either an electro-lyte or autocatalytic bath. A minimum thickness of 1 m
29、isrequired when the nickel is used as a base for subsequentdeposits.6.2.4 Heat Treatment:6.2.4.1 Heat treat in an inert gas atmosphere (for example,argon) for 1 to4hat540to800C. The exact time andtemperature should be selected by subjecting electroplated testpieces to adhesion or performance tests o
30、r both.6.2.4.2 The heat treatment can be performed after all elec-troplated coatings have been applied or immediately after thenickel electroplating. This latter approach is used in certaincases, for example, when undesirable diffusion can occurbetween the nickel and the subsequent deposit. If the h
31、eattreatment is performed before applying the subsequent deposit,3The boldface number in parentheses refers to the list of references at the end ofthis standard.B481 68 (2013)2the nickel will have to be activated before continuing theelectroplating. Methods of activation are given in PracticeB343.RE
32、FERENCES(1) Hands, S., U. S. Patent 2,734,837, Feb. 14, 1956.(2) Beach, J. G., “Status of Electroplated Metal Coatings on Titanium,”DMIC Memorandum, BMMI, Defense Metals Information Center,Battelle Memorial Institute, Columbus, Ohio, May 10, 1957.(3) Beach, J. G. and Gurklis, J. A., “Procedures for
33、ElectroplatingCoatings on Refractory Metals,” DMIC Memorandum 35, BMMI,Defense Metals Information Center, Battelle Memorial Institute,Columbus, OH, Oct. 9, 1959.(4) Colner, W. H., Feinleib, M. and Reding, J. H., Journal Electrochemi-cal Soc. Vol 100, 1953, pp. 485489.(5) Foisel, W. J. and Ellmers, C
34、. R., U. S. Patent 2,946,728, July 26, 1960;British Patent 814-326, June 3, 1959.(6) Halpert, D., U. S. Patent 2,921,888, Jan. 19, 1960.(7) Harding, W. B., “Electroplating on Titanium and Titanium Alloys,”Plating, Vol 50, 1963, pp. 131135.(8) Keller, E. W. and Gross, W. M., “Electroplating on Titani
35、um,” Report9733, Convair, San Diego, June, 1956.(9) Lee, W. G., U. S. Patent 2,928,757, March 15, 1960.(10) Levy, M. and Romulo, J. B., Proceedings, Amer. ElectroplatersSoc., Vol 48, 1961, p. 135.(11) McCargar, J. V., Pohl, S. W., Hyink, W. J. and Hanrahan, M. W.,“Development of Titanium and Titaniu
36、m Alloy Gears for Aircraftand Guided Missile Components,” Armed Services Tech. Infor.Agency Report 214580.(12) Missel, L., Proceedings, Amer. Electroplaters Soc. Vol 43, p. 17(1959); Metal Finishing, Vol 55, No. 9, 1957, pp. 4654.(13) Stanley, C. and Brenner, A., Proceedings, Amer. Electroplaters So
37、c.Vol 43, 1956, pp. 123127.(14) Marshall, W. A., Transactions, Inst. Metal Finishing, Vol 44, 1966,pp. 111118.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised
38、 that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either rea
39、pproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If yo
40、u feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual
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