Hardness is one of the important mechanical properties of coatings. The hardness of the coating is determined by the crystal structure of the coating metal. In order to eliminate the influence of the base material on the coating and the limitation of the indentation size caused by the thickness of the coating, the microhardness method is generally used. That is, a special diamond indenter on a microhardness tester is used to press into the coating surface or section of the sample under a certain static load to obtain the corresponding square pyramid indentation. Then use the hardness upper micrometer eyepiece to magnify the indentation to a certain magnification and measure the diagonal length of the indentation.