| 摘要 |
A spherical powder selected from the group consisting of titanium nitride, titanium carbonitride, titanium nitride containing a metal of the IVa, Va and VIa group of the periodic table, and titanium carbonitride containing a metal of the IVa, Va and VIa group of the periodic table, having an average grain size of more than 2 mu m and a narrow grain spectrum, is prepared by introducing into a reaction vessel a mixture of at least one substance selected from the group consisting of titanium metal, a metal of the IVa, Va and VIa group of the periodic table, and an oxide, carbide, nitride and carbonitride of said metals, and a carbon-containing substance, establishing a nitrogen atmosphere in the reaction vessel, heating the mixture in the reaction vessel to a temperature between 800 DEG C. and 2400 DEG C. and maintaining the temperature between 1400 DEG C. and 2000 DEG C. until gaseous reaction products are produced, removing the gaseous reaction products as they are produced while contacting the mixture with nitrogen or a nitrogen-generating gas, evacuating the reaction vessel to a pressure of < 10 mbar and subsequently flooding the same with nitrogen or a nitrogen-generating gas to a pressure of 50 to 1000 mbar, repeating the evacuation and flooding cycles several times, and cooling the resultant reaction product in the reaction vessel.
|
