Structure and wear properties of laser gas nitrided NiTi surface

The laser gas nitriding process is an efficient technique for modification of materials. Composite coatings with a microstructure consisting of dendritic TiN/NiTi were fabricated on a substrate of NiTi by the laser gas nitriding process. Different nitrogen flow rates were supplied during the laser process in order to detect the influence of the TiN on the wear resistance. The wear resistance of the TiN/NiTi coatings was evaluated under sliding wear test conditions in 5% NaCl aqueous solution at room temperature. The results indicate that the TiN/NiTi coatings have excellent abrasive and adhesive wear resistance because of the high hardness and the proportion of the TiN.