Formation of titanium nitride produced from nanocrystalline titanium powder under nitrogen atmosphere

The initially globular-shaped Ti powder particles were flattened to 'pan-cake' like shape after 12, 16, and thin flakes after 20 h of mechanical milling. Although no change peak positions of HCP Ti crystal structure, the increase in peak intensity with milling time was evident. It is found that the greater surface to volume ratio of the milled Ti powders accelerated the N-2 uptake and subsequent formation of TiN at lower temperatures (884, 856 and 833 degrees C for 12, 16 and 20 h, respectively) than in the unmilled powder (similar to 1100 degrees C). Higher nitrogen content of 41-44 at.% by EDS analysis confirmed the high rate of dissolution on the milled powders. (C) 2010 Elsevier Ltd. All rights reserved.