Phase transition and mechanical properties of ZrNxOy thin films on AISI 304 stainless steel

► Phase transition in the ZrNxOy film is from ZrN, Zr2ON2, to m-ZrO2 with O2 flow rate. ► Residual stress decreases with increasing O2 flow rate in the three major phases. ► The hardness of ZrNxOy films is mostly decreased with increasing oxygen content. ► Wettability of the three main phases on 304SS was measured using Owens-Wendt method. ► ZrO2 interlayer may lead to the spallation of the ZrNxOy films after salt spray test.