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A new synthesizing method for producing submicron TiC powders was studied by using TiH 2 and carbon black powders. It is well known that hydrogen absorption transforms titanium from metal (h.c.p.) to brittle hydride (f.c.c.) powders by ball-milling. This research focused on obtaining submicron-sized TiC powders from the ball-milled mixture of TiH 2 and carbon black by thermal treatment. The hydrogen, carbon, iron, and oxygen composition changes in the mixed powders were analyzed. Thereafter, a differential thermal analysis (DTA) test was performed to observe change of phase with ball-milling time. The TiC powders were obtained by heat treating the powders milled for 5 h at various temperatures (600-1200 o C). The phase microstructure was investigated via DTA, X-ray diffraction (XRD), and scanning electron microscope (SEM). The mixture milled for 2 h had an f.c.t. structure containing 66.73 at.%H transformed to f.c.c. by milling for 4 h. After 5 h of ball-milling, submicron-sized particles of 273 nm were obtained. At the isothermal heat-treating temperature of 500 o C, the Ti single phase was formed completely, and the TiC phase of lattice parameter 0.310 nm was completely formed over the temperature of 1000 o C.

<p>Two sintering methods of a pressureless sintering and a spark-plasma sintering are tested to densify the Fe- TiC composite powders which are fabricated by high-energy ball-milling. A powder mixture of Fe and TiC is prepared in a planetary ball mill at a rotation speed of 500 rpm for 1h. Pressureless sintering is performed at 1100, 1200 and 1300°C for 1-3 hours in a tube furnace under flowing argon gas atmosphere. Spark-plasma sintering is carried out under the following condition: sintering temperature of 1050°C, soaking time of 10 min, sintering pressure of 50 MPa, heating rate of 50°C, and in a vacuum of 0.1 Pa. The curves of shrinkage and its derivative (shrinkage rate) are obtained from the data stored automatically during sintering process. The densification behaviors are investigated from the observation of fracture surface and cross-section of the sintered compacts. The pressureless-sintered powder compacts show incomplete densification with a relative denstiy of 86.1% after sintering at 1300°C for 3h. Spark-plasma sintering at 1050°C for 10 min exhibits nearly complete densification of 98.6% relative density under the sintering pressure of 50 MPa.</p>