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

This specification establishes the requirements for electrodeposited palladium coatings for use in engineering applications. This specification also covers composite coatings of palladium with a thin gold overplate for applications involving electrical contacts. The plating system shall indicate the basis metal involved, thickness of the underplates, thickness of the palladium coating, and grade of the gold overplate. Coatings shall be sampled, tested, and conform accordingly to specified requirements as to purity, appearance, thickness, dutility, adhesion (to be examined either by bend, heat, or cutting test), and integrity (gross defects, mechanical damage, and porosity).1.1 This specification covers requirements for electrodeposited palladium coatings containing at least 99.7 mass % of palladium metal. Composite coatings consisting of palladium with a thin gold overplate for applications involving electrical contacts are also covered.1.2 Properties—Palladium is the lightest and least noble of the platinum group metals. It has a specific gravity of 12.0, which is substantially less than gold (19.3) and platinum (21.5). This yields a greater volume or thickness of coating and, consequently, some saving of metal weight accompanied by a small sacrifice in corrosion resistance and reflectivity. The following table compares the hardness range of electrodeposited palladium with other electrodeposited noble metals and alloys (1,2).2  Approximate Hardness (HK25)Gold 50–250Palladium 75–600Platinum 150–550Palladium-Nickel 300–650Rhodium 750–1100Ruthenium 600–13001.3 The values stated in SI units are the preferred values. Values provided in parentheses are for information only.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.