1、Designation: B 481 68 (Reapproved 2003)e1Standard 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,
2、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.e1NOTESection 3.1 was editorially updated in May 2003.INTRODUCTIONFull utilization of the light weight and high stren
3、gth of titanium is prevented by the tendency it hasto gall 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 form
4、s an adherent oxide coating in the presence ofoxygen and 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 t
5、hat have been foundto be successful in producing adherent 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 publ
6、ished work on electroplatingon titanium is given in the list 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
7、safety and health practices and determine the applica-bility of regulatory limitations prior to use. For a specifichazard statement, see 3.1.2. Referenced Documents2.1 ASTM Standards:B 343 Practice for Preparation of Nickel for Electroplatingwith Nickel23. Reagents3.1 Purity of ReagentsAll acids and
8、 chemicals used inthis practice are technical grade. Acid 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/
9、mLHydrofluoric acid 100 mass %, density 1.0005 g/mLNitric 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 vap
10、or degreasing, alka-line cleaning, grinding, or blasting.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 pr
11、ocess has been demonstrated to be successful are givenhere. 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-4M
12、n, and 3Al-5Cr.1This practice is under the jurisdiction of ASTM Committee B08 on Metallicand Inorganic Coatingsand is the direct responsibility of Subcommittee B08.02onPre Treatment.Current edition approved Feb. 10, 2003. Pblished May 2003. Originallyapproved in 1968. Last previous edition approved
13、in 1997 as B 48168 (1997).2Annual Book of ASTM Standards, Vol 02.05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2.1.2 PickleImmerse in the following solution, at roomtemperature, until red fumes are evolved:HF (60 mass %) 1 vol
14、ume 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).Standard 3Al-5CrNa2Cr2O72H2O 250 g/L 390 g/LHF (60 % mass) 48 mL/L 25 mL/LTemperature 82 to 100C 82 to 100CNOTE 1For platinu
15、m electroplating on commercially pure titanium,etching may be done by immersion for 5 min in hot (94C min)concentrated hydrochloric acid followed by rinsing 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
16、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 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 mech
17、anicaland, therefore, although of a relatively high order of magni-tude, it may be less than adequate. If a higher degree ofadhesion is desired, use nickel as an intermediate coating andheat treat. This causes interdiffusion of the nickel and titaniumand produces a metallurgical bond. The heat treat
18、ment can beperformed after all electroplating is applied or immediatelyafter the nickel electroplating. This later approach is used incertain 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 examp
19、le,argon) for 1 to4hat540to800C. The exact time andtemperature should be selected by subjecting electroplated testpieces to adhesion or 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 th
20、e 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 procedure is suitable for commerciallypure titanium and 4Al-4Mn alloy. The adhesion produced ispurely mechanical but sufficient to pass a bend test and hea
21、tingin 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 %) 3 volumes5.2.3 Rinse.5.2.4 EtchImmerse in the following solution and makeanodic, raising the current above the operating value until localchemica
22、l 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/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
23、 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,less concentrated grades of hydrofluoric acid cannot be substi-tuted for the 71 % grade. The solution or part should be mildlyagitated. The cathodes
24、 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 current densities will produce electropol-ishing and inadequate current densities will permit localchemical attack. Both conditions will result in la
25、ck 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 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 CleanSe
26、e 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,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 a
27、chieved. 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 or dimensional changes. The grit should be usedexclusively for blasting titanium to avoid imbedding of con-taminants such as iron that can cause local
28、 failures in thecoating.6.2.3 ElectroplatingDeposit nickel from either an electro-lyte or autocatalytic bath. A minimum thickness of 1 m 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 to
29、4hat540to800C. The exact time andtemperature should be selected by subjecting electroplated testpieces to adhesion or performance tests or 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 a
30、pproach is used in certaincases, for example, when undesirable diffusion can occurbetween the nickel and the subsequent deposit. If the heattreatment is performed before applying the subsequent deposit,3The boldface number in parentheses refers to the list of references at the end ofthis standard.B
31、481 68 (2003)e12the nickel will have to be activated before continuing theelectroplating. Methods of activation are given in PracticeB 343.REFERENCES(1) Beach, J. G., “Status of Electroplated Metal Coatings on Titanium,”DMIC Memorandum, BMMI, Defense Metals Information Center,Battelle Memorial Insti
32、tute, Columbus, Ohio, May 10, 1957.(2) Beach, J. G. and Gurklis, J. A., “Procedures for ElectroplatingCoatings on Refractory Metals,” DMIC Memorandum 35, BMMI,Defense Metals Information Center, Battelle Memorial Institute, Co-lumbus, OH, Oct. 9, 1959.(3) Colner, W. H., Feinleib, M. and Reding, J. H.
33、, 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 814-326, 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., “El
34、ectroplating on Titanium and Titanium Alloys,”Plating, Vol 50, 1963, pp. 131135.(8) Keller, E. W. and Gross, W. M., “Electroplating on Titanium,” 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. Elec
35、troplaters Soc.,Vol 48, 1961, p. 135.(11) McCargar, J. V., Pohl, S. W., Hyink, W. J. and Hanrahan, M. W.,“Development of Titanium and Titanium Alloy Gears for Aircraft andGuided Missile Components,” Armed Services Tech. Infor. AgencyReport 214580.(12) Missel, L., Proceedings, Amer. Electroplaters So
36、c. 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, pp. 123127.(14) Marshall, W. A., Transactions, Inst. Metal Finishing, Vol 44, 1966,pp. 111118.ASTM International takes no position respecting t
37、he validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard
38、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 withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International H
39、eadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you 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
40、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 (2003)e13
