Residual stress measurements on CrN/Cr/CrN multilayer PVD coatings

Hard physical vapour deposition (PVD) based coatings for wear and corrosion protection are successfully being applied in many engineering applications. Nitrides of transition metals, such as CrN, TiN, NbN, have been widely studied, however, because most vapour deposited coatings are relatively thin, they usually offer less resistance to the bulk surface deflection. One approach to overcome this aspect is to adopt multilayer coatings with hard/soft (or high/low elastic modulus) layers. Nevertheless, the residual stress induced during the fabrication process is an important factor that needs to be address, which can limit the coating performance. The present paper is concerned with the residual stress present in multilayer CrN/Cr/CrN coatings produced by cathodic arc evaporation. Three different steel substrates were employed (i.e. AISI H13, AISI 1040 and K340). These substrates were subsequently coated in the sequence CrN (1.6μm)/Cr/CrN (1.6 μm), using three different intermediate Cr layer thickness (i.e. 0.5, 1.0, and 1.6 μm). X-ray diffractometry (XRD) was used to evaluate the strain in the direction perpendicular to the coating surface so as to determine the mean residual stress in the coating. © ASM International