Auger‐depth profiling experiments of mechanically thinned samples were carried out with TiN films deposited on n‐type (100)silicon wafers, stainless steel, and high‐speed steel (HSS). The films were deposited between 700 and 800 K by triode ion plating based on the electron beam evaporation of titanium in an atmosphere containing both nitrogen and argon. All the films studied showed a Ti‐rich interfacial layer and higher nitrogen concentration near the surface. An intermediate interfacial transition layer consisting of TiN, titanium, and silicon was found on the Si substrates. Interfacial layers of CrO2 and SiO2 were detected on stainless steel and vanadium carbides underneath the TiN coating remained after crater wear testing. Consequently, vanadium carbide and epitaxial growth of the TiN coating at these carbides is expected to be responsible for the remarkably good adhesion of TiN to HSS.