Forming carbonitride coatings on titanium by thermochemical treatment with C-N-O-containing media

The formation of TiC_xN_y coatings on titanium alloys through thermochemical treatment of graphite in nitrogen was investigated in this study. The presence of oxygen in saturating media was found to lower the nitrocarburizing temperature from 1,100°C to 850°C. Two methods to accumulate oxygen in a saturating medium have been proposed: using oxygen-containing nitrogen or oxygensaturated graphite. The sequence of stages of carbonitride formation in the Ti-C-N-O system is explained in this paper.