【国外标准】 Standard Specification for Electroplated Engineering Nickel Coatings

This specification covers the requirements for electroplated nickel coatings applied to metal products for engineering applications (for example, for use as a buildup for mismachined or worn parts), for electronics applications (including as underplates in contacts or interconnections), and in certain joining applications. Coatings shall be available in any one of the following types: Type 1, coatings electroplated from solutions not containing hardeners, brighteners, or stress control additives; Type 2, electrodeposits used at moderate temperatures, and contain sulfur or other codeposited elements or compounds that are present to increase the hardness, refine grain structure, or control internal stress; and Type 3, electroplates containing dispersed submicron particles such as silicon carbide, tungsten carbide, and aluminum oxide that are present to increase hardness and wear resistance at specified temperatures. Metal parts shall undergo pre- and post-coating treatments to reduce the risk of hydrogen embrittlement, and peening. Coatings shall be sampled, tested, and conform accordingly to specified requirements as to appearance, thickness (measured either destructively by microscopical or coulometric method, or nondestructively by magnetic or X-ray method), adhesion (examined either by bend, file, heat and quench, or push test), porosity (assessed either by hot water, ferroxyl, or flowers of sulfur test), workmanship, and hydrogen embrittlement relief.1.1 This specification covers the requirements for electroplated nickel coatings applied to metal products for engineering applications, for example, for use as a buildup for mismachined or worn parts, for electronic applications, including as underplates in contacts or interconnections, and in certain joining applications.1.2 Electroplating of nickel for engineering applications (Note 1) requires technical considerations significantly different from decorative applications because the following functional properties are important:1.2.1 Hardness, strength, and ductility,1.2.2 Wear resistance,1.2.3 Load bearing characteristics,1.2.4 Corrosion resistance,1.2.5 Heat scaling resistance,1.2.6 Fretting resistance, and1.2.7 Fatigue resistance.NOTE 1: Functional electroplated nickel coatings usually contain about 99 % nickel, and are most frequently electrodeposited from a Watts nickel bath or a nickel sulfamate bath. Typical mechanical properties of nickel electroplated from these baths, and the combined effect of bath operation and solution composition variables on the mechanical properties of the electrodeposit are given in Guide B832. When electroplated nickel is required to have higher hardnesses, greater wear resistance, certain residual stress values and certain leveling characteristics, sulfur and other substances are incorporated in the nickel deposit through the use of certain addition agents in the electroplating solution. For the effect of such additives, see Section 4 and Annex A3. Cobalt salts are sometimes added to the plating solution to produce harder nickel alloy deposits.1.3 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.1.4 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.