1、Designation: B 481 68 (Reapproved 2008)Standard Practice forPreparation of Titanium and Titanium Alloysfor Electroplating1This standard is issued under the fixed designation B 481; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, th
2、e 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 gal
3、l 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
4、water. 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
5、 electrodeposits 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 l
6、ist 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-bil
7、ity of regulatory limitations prior to use. For a specifichazard statement, see 3.1.2. Referenced Documents2.1 ASTM Standards:2B 343 Practice for Preparation of Nickel for Electroplatingwith Nickel3. Reagents3.1 Purity of ReagentsAll acids and chemicals used inthis practice are technical grade. Acid
8、 solutions are based uponthe following assay materials (WarningUse hydrofluoricacid with 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
9、 acid 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.
10、4.2 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 givenher
11、e. 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 sol
12、ution, at roomtemperature, until red fumes are evolved:HF (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 formulation is recommended for3Al-5Cr alloy).1This practice is under the jurisdiction of ASTM
13、Committee B08 on Metallicand Inorganic Coatings and is the direct responsibility of Subcommittee B08.02 onPre Treatment.Current edition approved Aug. 1, 2008 Published September 2008. Originallyapproved in 1968. Last previous edition approved in 2003 as B 48168 (2003)e1.2For referenced ASTM standard
14、s, 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 Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
15、9428-2959, United States.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 acid followed by ri
16、nsing and platinum electro-plating (6)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 desired, firstapply a
17、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 of magni-tude, it may be less than adequate. If a higher degree ofadhesion is desired, use ni
18、ckel 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 incertain cases, fo
19、r 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 performance tes
20、ts 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 B 343.5. Process No. 25.1 CleanSee 4.1.5.2 Electrochemical Etch:5.2.1 The following proced
21、ure 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 andHNO3(69 mass
22、 %) 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 anodically at 5.4 A/dm
23、2for 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 high; therefore
24、,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.5.2.4.4 Excessive
25、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 preceded by a
26、 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, 2.5Al-16V,4A
27、l-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 of thesurface o
28、r 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 isrequired whe
29、n 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 or both.6.2.4.2
30、 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 heattreatment i
31、s performed before applying the subsequent deposit,the nickel will have to be activated before continuing theelectroplating. Methods of activation are given in PracticeB 343.3The boldface number in parentheses refers to the list of references at the end ofthis standard.B 481 68 (2008)2REFERENCES(1)
32、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.(2) Beach, J. G. and Gurklis, J. A., “Procedures for ElectroplatingCoatings on Refractory Metals,” DMIC Memorandum 35,
33、 BMMI,Defense Metals Information Center, Battelle Memorial Institute, Co-lumbus, OH, Oct. 9, 1959.(3) Colner, W. H., Feinleib, M. and Reding, J. H., Journal ElectrochemicalSoc. Vol 100, 1953, pp. 485489.(4) Foisel, W. J. and Ellmers, C. R., U. S. Patent 2,946,728, July 26, 1960;British Patent 814-32
34、6, June 3, 1959.(5) Halpert, D., U. S. Patent 2,921,888, Jan. 19, 1960.(6) Hands, S., U. S. Patent 2,734,837, Feb. 14, 1956.(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 Titanium,” Report9
35、733, 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. Electroplaters Soc.,Vol 48, 1961, p. 135.(11) McCargar, J. V., Pohl, S. W., Hyink, W. J. and Hanrahan, M. W.,“Development of Titanium and TitaniumAlloy Gears
36、forAircraft andGuided Missile Components,” Armed Services Tech. Infor. AgencyReport 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 Soc.Vol 43, 1956,
37、 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 that determina
38、tion 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 reapproved or with
39、drawn. 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 you feel that you
40、r 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 reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B 481 68 (2008)3
