Structure and Hardness of Ceramics Produced through High-Temperature Nitridation of Titanium Foil

Abstract

We have studied the variation in the phase composition, elemental composition, and microstructure of rolled titanium samples during thermal annealing in a nitrogen atmosphere at 1300, 1500, 1700, and 2000°C. The results demonstrate that the nitridation process can yield compact titanium nitride-based ceramics or TiN/TiN_x/α-Ti〈N〉 heterostructures. X-ray diffraction data for the near-surface region of the samples before and after nitridation and those for cross-sectional fracture surfaces of heterostructures are used to infer orientation relationships between the TiN phase and α-Ti〈N〉 solid solution. Scanning electron microscopy results for cross-sectional fracture surfaces indicate that complete nitridation of the samples leads to the formation of a three-layer microstructure.