Formation of nanometric hard materials by cold milling

The fabrication of nanosized, single crystal TiC or TiN powders from ilmeni te or TiO2 within a single low temperature stage is reported in this paper. The titaniferous powders were ball milled for 100 h in a laboratory scale mill with magnesium powder and either graphite or nitrogen. The resultant p owders were then subjected to an annealing step at 1200 degrees C. Differen tial thermal analysis and X-ray diffraction showed that the phases formed w ithin the milling step and underwent grain growth on annealing. Acid leachi ng of the powders selectively removed the unwanted product phases leaving o nly the hard material. The final particle size and Scherrer XRD crystallite size were similar after annealing, implying that the particles produced we re single crystal. (C) 1999 Elsevier Science Ltd. All rights reserved.