JIS K5633-2002 "Coatings Containing Phosphoric Acid" specifies the technical requirements and application specifications for coatings containing phosphoric acid (i.e. acid etching primers). The coating is mainly used for the pretreatment of metal surfaces, which can enhance the adhesion between the coating and the substrate through chemical reactions, and at the same time has anti-corrosion effect. The standard details the performance requirements of the coating composition, acidity, adhesion, corrosion resistance, etc., and provides clear guidance on the coating process, coating film thickness, application conditions and quality control. Through the implementation of this standard, it is designed to improve the adhesion and anti-corrosion performance of coatings, ensure the durability of coatings in harsh environments, and promote the wide application of phosphoric acid-containing coatings in various industrial fields.