Titanium Nitriding by Microwave Atmospheric Pressure Plasma: Towards Single Crystal Synthesis

High temperature titanium nitriding is achieved by plasmas sustained at atmospheric pressure in a microwave resonant cavity. TiN layers produced in the temperature range (1475-1980 K) present a grain orientation that is mainly defined by initial grain orientation of the titanium substrate. Coarsening pretreatments on the titanium samples before nitriding allows the synthesis of a strongly oriented TiN layer. The TiN + alpha-Ti layer thickness reaches about 116 mu m after a 1 h treatment at 1760 K. For these treatment times, the bulk material is not totally transformed into TiN, but this is a first step towards the synthesis of single crystals of TiN from commercial-grade pure titanium.