This study was investigated in carbon diffusion behavior of laser-carburized TiZrN coating layer and the changesof mechanical properties. The carbon paste was deposited on TiZrN coatings, and the laser was irradiated to carburize intothe coatings. The XRD peak corresponding to the (111) plane shifted to a lower angle after the carburization, showing thelattice expansion by doped carbon. The decreased grain size implied the compression by the grain boundary diffusion ofcarbon. The XPS spectra for the bonding states of carbon was analyzed that carbon was substitute to nitrogen atoms inTiZrN, as carbide, through the thermal energy of laser. In addition, the combination of sp2 and sp3 hybridized bondsrepresented the formation of an amorphous carbon. The cross-sectional TEM image and the inverse FFT of the TiZrNcoating after carburizing were observed as the wavy shape, confirming the amorphous phase located in grain boundaries.
After the carburization, the hardness increased from 34.57 GPa to 38.24 GPa, and the friction coefficient decreased by83 %. In particular, the ratio of hardness and elastic modulus (H/E) which is used as an index of the elastic recovery,increased from 0.11 to 0.15 and the wear rate improved by 65 %.