A technique to enhance adhesion of hard coatings to substrate by using compositionally gradient interlayers has been applied for TiN/Ti/TiO2 and ZrN/Zr/ZrO2 multi-compositional coatings. The coatings were prepared by dc reactive magnetron sputtering using a Zr or a Ti Target. Adhesion of coatings to a borosilicate glass substrate was estimated by a scratch method. The hardness of coatings was measured by a nano-indentation method. Without a underlayer, ZrN coatings showed very poor adhesion. By using compositionally gradient underlayers, the adhesion strength of ZrN hard coatings was enhanced drastically up to adhesion strength values almost equal to oxide singlelayer coatings. The increase in hardness by inserting compositionally gradient underlayers was observed in ZrN/Zr/ZrO2 system.
