Multiphase films bearing Ti2AlN by pulse plasma hollow cathode nitriding

This study aims to resolve the wear resistance and extend the use of titanium aluminides. A novel method of obtaining multiphase films bearing Ti2AlN on the Ti-Al alloys is put forward. The Ti1-xAlx (x=0.25, 0.33 and 0.47) alloys were nitrided in a pulse plasma hollow cathode environment at 800-900 degrees C for various durations in a mixture of 50%N-2 and 50%H-2 under pressures of 1.50-3.00 torr. The results show that the nitriding gas pressure has a strong influence on the phase structure of the surface films. The forming phases in the films are mainly composed of Ti2AlN and TiN compounds. The presence of Ti2AlN in the wear tracks apparently reduces the friction coefficient of the samples. The hardened phase TiN in the film improves the wear resistance of the Ti-33Al alloy.