ASTM B481-2019 pdf free download
ASTM B481-2019 pdf free download.Standard Practice for Preparation of Titanium and Titanium Alloys for Electroplating
1. Scope
1.1 This practice describes processes that have been found to be successful in producing adherent electrodeposits of good quality on titanium and certain titanium alloys. Not all of the processes that have been reported as successful are described, but rather three basic ones that have had the widest use. A rather complete listing of the published work on electroplating on titanium is given in the list ofreferences which appear at the end of this practice. 1.2 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 appro- priate safety, health, and environmental practices and deter- mine the applicability of regulatory limitations prior to use. For a specific hazard statement, see 3.1. 1.3 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Process No. 1
4.1 Cleaning—Remove oil, grease, and other soil by appro- priate conventional processes such as vapor degreasing, alka- line cleaning, grinding, or blasting.4.2 Activating—Activation may be done by chemical or electrochemical etching or liquid abrasive blasting. It is pos- sible that all three processes will work equally well on pure titanium and all common alloys; however, only those for which each process has been demonstrated to be successful are given here. The suitability of a process for an alloy not listed should be experimentally determined before committing production parts. 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 Pickle—Immerse in the following solution, at room temperature, until red fumes are evolved: HF (60 mass %) 1 volume and HNO 3 (69 mass %) 3 volumes 4.2.1.3 Rinse. 4.2.1.4 Etch—Immerse in the following aqueous solution for 20 min (Note that a special formulation is recommended for 3Al-5Cr alloy).N OTE 1—For platinum electroplating on commercially pure titanium, etching may be done by immersion for 5 min in hot (94 °C min) concentrated hydrochloric acid followed by rinsing and platinum electro- plating (1). 3 4.2.2 Rinse. 4.2.3 Electroplate—Electroplate with chromium, with cop- per from an acid bath, or with nickel from either a Watts or sulfamate bath, or deposit nickel in an autocatalytic bath. If a deposit of some metal other than these three is desired, first apply a nickel coating with a minimum thickness of 1 µm followed by the desired final metal. 4.2.4 Heat Treat: 4.2.4.1 The adhesion of the electrodeposit is mechanical and, therefore, although of a relatively high order of magnitude, it may be less than adequate. If a higher degree of adhesion is desired, use nickel as an intermediate coating and heat treat. This causes interdiffusion of the nickel and titanium and produces a metallurgical bond. The heat treatment can be performed after all electroplating is applied or immediately after the nickel electroplating. This later approach is used in certain cases, for example, when undesirable diffusion can occur between the nickel and the subsequent deposit. 4.2.4.2 Heat treat in an inert gas atmosphere (for example, argon) for 1 to 4 h at 540 to 800 °C. The exact time and temperature should be selected by subjecting electroplated test pieces to adhesion or performance tests, or both. 4.2.4.3 If the heat treatment is performed before applying the subsequent deposit, the nickel will have to be activated before continuing the electroplating. Methods of activation are given in Practice B343.
