Abstract:

Direct current (DC) nitrogen arc melting technique is presented, which allows for insitu preparing TiN layers on Ti-6Al-4V substrate. The microstructures，hardness and wear properties of the TiN layers were investigated by scanning electron microscopy, X-ray diffraction and microhardness testing instrument. The effects of arc current on microstructure and properties of TiN layers were discussed. The TiN layer is mainly composed of TiN dendrites and the content of the TiN dendrites gradually decreased. The TiN layer has a good metallurgical bonding with substrate. With an increase of arc current from 60 A to 100 A, the amount of TiN dendrites increased, and the layer hardness and wear resistance enhanced. At the condition of 100 A, the TiN layer highest hardness reached 1885 HV which is about 5 times that of substrate. At the same time, the wear resistance of TiN layer was significantly increased.

Key words: surface and interface of materials, nitrogen arc, nitrided, microstructure, wear