Coating quality inspection item 1) Appearance of the coating The appearance of the coating is one of the items that must be inspected for any part or coating. Usually, the appearance of the coating is directly observed with the naked eye under natural light. Its content includes the macroscopic uniformity, color, brightness, crystallization status, and macroscopic adhesion of the forged layer. Generally speaking, in addition to its unique color and luster, the coating should also be uniform, meticulous, and have good adhesion. It is not allowed to have pinholes, stripes, blistering, peeling, burrs, nodules, pits, scorching, cracking, peeling, peeling, abnormal color or leakage. However, for plated parts, slight defects are generally allowed at the hook. 2) The thickness of the coating must ensure the usability of the parts, and the coating on the surface of the parts must reach a certain thickness. The commonly used methods for measuring coating thickness include destructive and non-destructive methods. Destructive thickness measurement methods include anodic dissolution Coulomb method, metallographic method, dissolution weighing method, liquid flow method, droplet method, etc; Non destructive thickness measurement methods include mechanical measuring tool method, magnetic method, eddy current method β X-ray backscattering method, X-ray spectroscopy, etc. When using these methods to measure the thickness of the coating, please refer to the corresponding national standards. 3) There are two main types of test methods for evaluating the corrosion resistance of coatings: natural environment testing and artificial accelerated corrosion testing. The former includes on-site tests in the operating environment and atmospheric exposure tests under different climatic conditions. This type of method can truly evaluate the corrosion resistance of the coating, but the disadvantage is that the cycle is too long; The latter includes neutral salt spray test (nss), copper acetate accelerated test (cass), corrosion paste test, electrolytic corrosion test, industrial gas corrosion test, damp heat test, etc. All these corrosion resistance tests have corresponding national standards that specify the test conditions and evaluation methods