Preparation of Ultrafine Tungsten-Molybdenum Composite Powder and Its Sintering Behavior

摘要

In this paper, a new method for preparing ultrafine tungsten-molybdenum composite powders has been proposed. The carbothermic pre-reduction of the mixture of molybdenum trioxide and tungsten trioxide with insufficient carbon black under argon atmosphere was carried out, to generate the pre-reduced tungsten-molybdenum composite powder containing a small amount of residual dioxide. Thereafter, the obtained reaction product was subjected to hydrogen reduction to remove the residual dioxide and generate pure tungsten-molybdenum composite powder with the particle size of 100-200 nm. Two kinds of ultrafine tungsten-molybdenum alloy powders (Mo-30 wt% W, Mo-70 wt% W) were prepared. The residual carbon of the finally obtained product was about 0.01-0.02 wt% after the hydrogen reduction. The sintering behavior of ultrafine W-Mo powders and the properties of sintered samples are investigated. After sintering ultrafine Mo-30 wt% W and Mo-70 wt% W powders at 1600 degrees C, the relative density of the sintered compacts was about 99%, 97%, and the microhardness were 287 HV and 350 HV, respectively. Meanwhile, as increasing the sintering temperature from 1200 to 1600 degrees C, the relative density and microhardness of the compacts gradually increased.