Carbon tool steel substrates were quenched after TiN coating by dc magnetron sputtering, and the effect of the substrate post quenching on the mechanical properties of TiN films were investigated. The residual stress of TiN film decreased by the substrate post quenching. Corresponding to this, the hardness of TiN film also decreased. On the other hand, the adhesive strength obtained by the scratch test and the substrate hardness were improved by the substrate post quenching. The reason why the adhesive strength was improved was explained by the following three effects of the substrate post quenching ; the decrease of the residual stress, the increase of the substrate hardness, and the formation of the mixing layer between the film and the substrate caused by elevated temperature in the post quenching procedure.
