Synthesis and Sintering of Tungsten and Titanium Carbide: A Parametric Study

Abstract

The three primary steps in the production of tungsten carbide WC and titanium carbide TiC powders are the preparation of the green mixture, carbidization by furnace annealing, and ball milling of the annealed products. This work performed a comprehensive parametric investigation of these three steps. The impact of several factors was examined including the carbon precursor, the mass and diameter of the milling bodies (balls), the milling time and speed, the temperature and length of the annealing process, the height of the powder in the furnace boats, and the rate at which the furnace boats move. Regression models for every stage of the process were verified by 10-fold validation and used to optimize the synthesis sequence, resulting in high-quality WC and TiC with a grain size below 2 microns and a content of free carbon below 0.1%. Additionally, solid solution (W,Ti)C was fabricated by mechanochemical synthesis from the elemental mixtures; however, further modification of this technique is necessary because of the observed relatively high concentration of residual free carbon (0.2–0.8%) and contamination by Fe.