Abstract This specification covers corrosion-resistant coating consisting of an inorganic aluminum particle-filled basecoat and an organic or inorganic topcoat. The basecoat is a water-dilutable slurry containing aluminum particles dispersed in a liquid binder of chromate/phosphate compounds. The organic topcoats consist of polymer resins and dispersed pigments. The inorganic topcoats consist of ceramic oxide pigments dispersed in a liquid binder of chromate/phosphate compounds. These coatings are applied by conventional dip/spin, dip/drain, or spray methods. The coating systems defined by this specification can be applied to ferrous alloy steels, aluminum, and ferritic and austenitic stainless steels. The inorganic aluminum particle-filled basecoat and the subsequent topcoats are classified into three groups, with subsequent subgroups. Materials shall be tested and the individual grades shall conform to specified values of appearance, adhesion, corrosion, thread-fit, weathering, coating thickness, and humidity. Scope 1.1 This specification covers the basic requirements for a corrosion-resistant coating consisting of an inorganic aluminum particle-filled basecoat and an organic or inorganic topcoat, depending on the specific requirements. 1.2 The coating may be specified with basecoat only, or with the top coated with compatible organic polymer or inorganic topcoats, depending on the specific requirements. 1.3 The basecoat is a water-dilutable slurry containing aluminum particles dispersed in a liquid binder of chromate/phosphate compounds. 1.4 The organic topcoats consist of polymer resins and dispersed pigments and are for service where temperatures do not exceed 230°C (450°F). 1.5 The inorganic topcoats consist of ceramic oxide pigments dispersed in a liquid binder of chromate/phosphate compounds and are for service where temperatures do not exceed 645°C (1200°F). 1.6 These coatings are applied by conventional dip/spin, dip/drain, or spray methods. 1.7 The coating process does not normally induce hydrogen embrittlement, provided that the parts to be coated have not been subjected to an acid cleaner or pretreatment (see Note 1). Note 1: Although this coating material contains water, it has a relatively low susceptibility to inducing hydrogen embrittlement in steel parts of tensile strengths equal to or greater than 1000 MPa (approximately RC31). Normal precautions for preparing, descaling, and cleaning steels of these tensile strengths must be observed. An initial stress relief treatment should be considered prior to any chemical treatment or cleaning operation. Acids or other treatments that evolve hydrogen should be avoided. Mechanical cleaning methods may be considered. Some steels are more susceptible to hydrogen embrittlement than others and may also require hydrogen embrittlement relief baking after cleaning but before coating. Since no process can completely guarantee freedom from embrittlement, careful consideration must be given to the entire coating process and the specific steel alloy employed. 1.8 The coating systems defined by this specification can be applied to ferrous alloy steels, aluminum, and ferritic and austenitic stainless steels. 1.9 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.10 The following safety hazards caveat pertains only to the test methods portion, Section 6, 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. 1.11 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.
