Study on the effect of welding on the properties of ceramic coating

Abstract The ceramic coating sprayed on the surface of the metal parts can protect the metal from corrosion by the medium in the environment and can also isolate the galvanic corrosion between the dissimilar metals, which is an effective anti-corrosion measure. Because the coefficient of thermal expansion between ceramic coating and metal parts is different, and the ceramic coating is mostly brittle material, the ceramic coating may crack when welding the metal parts sprayed with ceramic coating. The morphological characteristics of the ceramic coating with cracks were analyzed by means of color flaw detection and metallographic analysis. It was found that the cracks were networked and penetrated the ceramic layer. The properties of cracked ceramic coating were tested, and it was found that the sealing properties and anti-corrosion properties of cracked ceramic coating were weakened, and it could not pass the density test and salt spray test. The test results show that by increasing the distance between the weld and the ceramic coating, the ceramic coating on metal parts can effectively avoid cracking during welding.