Effect of hydro-jet treatment on the adhesion of the PVD coating to the carbide substrate as a method for pretreatment of the surface

Traditionally, the first stages of preparing a hard alloy for coating are various mechanical, electrical, chemical, and magnetic methods to change the surface quality, which usually increases the service life and wear resistance of the tool. Among other things, hydro-jet treatment, so exposure to a high-pressure water jet at a pressure of about 250 MPa, can be used when preparing the surface for coating. Grinded surfaces after hydro-treating show better adhesion of the coating by removing an excess of the cobalt bond smeared on the surface because it is highly flexible and poorly removed by the diamond grinding wheel. Besides, the surface roughness reduced. Wear tests using the spherical recess method showed a two-three fold improvement in the wear resistance of TiN-coated samples subjected to preliminary hydro-treatment. Besides, hydro-treating avoids surface contamination and eliminates any thermal effects.