【国外标准】 Standard Specification for Electrodeposited Coatings of Tin-Nickel Alloy

This specification establishes the requirements for electrodeposited tin-nickel alloy coatings from aqueous solutions intended for the corrosion protection of fabricated articles of iron, steel, zinc-base alloys, copper, and copper alloys. This specification does not apply to sheets, strips, or wires in the fabricated form. It also may not be applicable to finely threaded articles, but the decision to use the coating on such components may be made by the purchaser. Coating grades shall be designated by a service condition number, which indicates the severity of exposure for which the coating is intended, and a coating thickness notation. Iron and steel specimens shall undergo pre- and post-coating treatments for reducing the risk of hydrogen embrittlement. Coatings shall be sampled, tested, and conform to specified requirements as to appearance (visible defects), composition, thickness (assessed either by microscopical, magnetic, coulometric, beta backscatter, or X-ray spectrometry), adhesion (determined either by burnishing, or heat-quench test), and integrity (including gross defects, mechanical damage, and porosity).1.1 This specification covers the requirements for electrodeposited tin-nickel alloy coatings from aqueous solutions intended for the corrosion protection of fabricated articles of iron, steel, zinc-base alloys, copper, and copper alloys. The composition of the alloy remains constant at 65/35 tin-nickel in spite of wide fluctuations in both composition and operating conditions. The composition corresponds quite closely to an equiatomic ratio, and the process favors the co-deposition of tin and nickel atoms at identical rates.1.2 This specification does not apply to sheet, strip, or wire in the fabricated form. It also may not be applicable to threaded articles having basic major diameters up to and including 19 mm because of the nonuniformity of thickness that can be expected on fine threads. However, a decision to use the coating on such components may be made by the purchaser.1.3 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 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 appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.