Wear behavior of PACVD tin coatings deposited onto tool steels

Abstract
During cold forming processes like deep drawing of steel sheets, tools are subjected to various loads. During forming, Hertzian contact pressures and frictional forces cause fatigue and adhesion, respectively. Abrasion may, take place if wear particles are entrapped in the contact zone. Therefore, the aim of this work is to evaluate TiN coatings deposited by plasma assisted chemical vapor deposition (PACVD) onto tool steels with respect to adhesion, fatigue wear properties. Stoichiometric TiN coatings with different morphologies were deposited with and without plasma-nitriding of the steel substrate and characterized by X-ray diffraction (XRD) and scanning electron microsopy. The adhesion of the coatings was investigated using the VDI indention test and a surface fatigue test, where cyclic loads up to 80 kN are applied to the tool surface by cylindrical indenters. Adhesive wear of the coatings have been evaluated using a ball-on-disc tribometer. Abrasion resistance was characterized using a small-scale abrasive wear test.