LOW TEMPERATURE METHOD FOR SYNTHESIZING MICROGRAIN TUNGSTEN CARBIDE

摘要

2118596 9310042 PCTABS00022 A low temperature method for synthesizing micrograin tungsten carbide particles having an average diameter of 0.05 to 0.2 .mu.m includes the programmed heating of tungsten trioxide powder or other material containing tungsten in a flowing molecular hydrogen atmosphere having a constant proportion of molecular methane. The heating program is carried out at two different heating rates, the first being higher than the second. The first heating rate is 5 ·C to 50 ·C per minute from 25 ·C to 535 ·C. The second heating rate is 1 ·C to 10 ·C per minute from 535 ·C to about 850 ·C. The last temperature is then held until conversion of the tungsten trioxide or other tungsten-containing material to tungsten carbide is complete, typically from about 15 minutes to 3 hours.