【国外标准】 Standard Specification for Electrodeposited Coatings of Silver for Engineering Use

This specification establishes the requirements for electrodeposited silver coatings that may be mat, bright, or semibright, and are usually employed as solderable surfaces and for their electrical contact characteristics, high electrical and thermal conductivity, thermocompression bonding, wear resistance on load-bearing surfaces, and spectral reflectivity. Coatings shall be classified into types according to minimum purity, grade according to surface appearance (bright, semibright, or mat), and class according to whether any surface treatment has been applied. Coatings shall undergo preplating operations such as stress relief treatment, strike, and underplating, as well as post-plating embrittlement relief. Coatings shall be sampled, tested, and conform accordingly to specified requirements as to nature, purity, appearance, defects, adhesion, solderability, hardness, spectral reflectance, electrical conductivity, hydrogen embrittlement relief, and thickness (measured either nondestructively by beta backscatter, X-ray spectrometry, or magnetic method, or destructively by coulometric technique or microscopical cross-sectioning procedure).1.1 This specification covers requirements for electrodeposited coatings of silver used for engineering purposes that may be matt, bright, or semibright and are not less than 98 % silver purity.1.2 Coatings of silver covered by this specification are usually employed for solderable surfaces, electrical contact characteristics, high electrical and thermal conductivity, thermocompression bonding, wear resistance of load-bearing surfaces, and spectral reflectivity.1.3 In the Appendixes, important characteristics of electrodeposited silver coatings are briefly described which must be considered when used in engineering applications, namely electrical conductivity (see Appendix X1), silver migration (see Appendix X2), thickness (see Appendix X3), hardness (see Appendix X4), and atmospheric tarnish (see Appendix X5).1.4 The following hazards caveat pertains only to the test methods section of this specification: 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.