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ASTM B874-96(2008)

Заменен
Standard Specification for Chromium Diffusion Coating Applied by Pack Cementation Process — 3 стр.
Реферат

This specification covers the requirements for chromium diffusion of metals applied by pack cementation process. The four classes of chromium diffusion coating, defined by the type of base metal, are as follows: Class I (carbon steels); Class II (low-alloy steels); Class III (stainless steels); and Class IV (nickel-based alloys). Specimens shall adhere to processing requirements such as substrate preparation, materials (masteralloys, activators, and inert fillers), loading, furnace cycle, post cleaning, post straightening, visual inspection, and marking and packaging. Specimens shall also adhere to coating requirements such as diffusion thickness, decarburization, chromium content, appearance, and mechanical properties (tensile strength, and macro- and micro-hardness).

Область применения

1.1 This specification covers the requirements for chromium diffusion of metals by the pack cementation method. Pack diffusion employs the chemical vapor deposition of a metal which is subsequently diffused into the surface of a substrate at high temperature. The material to be coated (substrate) is immersed or suspended in a powder containing chromium (source), a halide salt (activator), and an inert diluent such as alumina (filler). When the mixture is heated, the activator reacts to produce an atmosphere of chromium halides which transfers chromium to the substrate for subsequent diffusion. The chromium-rich surface enhances corrosion, thermal stability, and wear-resistant properties.

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 and health practices and determine the applicability of regulatory limitations prior to use.

ICS
25.220.40 Metallic. Including electrolytic depositions, cathodic coatings, autocatalytic coatings, etc. / Металлические покрытия. Включая электролитическое осаждение, катодные покрытия и т.д.
Сборник ASTM
02.05 Metallic and Inorganic Coatings; Metal Powders and Metal Powder Products / Металлические и неорганические покрытия, Металлические порошки, изделия из металлического порошка
Тематика
Paints & Related Coatings