PREPARATION OF ZrB_2 BY BORO/CARBOTHERMAL REDUCTION IN SPS DEVICE

摘要

ZrB2 ceramics were prepared by boro/carbothermal reduction, using spark plasma sintering (SPS). This technology allows to control and monitor the ongoing reduction reaction during the sintering of ZrO2 and B4C powder mixtures with graphite, leading to the production of ZrB2. This work shows the effect of several parameters on the amount of produced ZrB2. The results are compared with literature data. Sintering temperatures in the range 1400 -1800 degrees C were chosen for the experiment. For example, after sintering at a temperature of 1800 degrees C, with a hold time of 15 min, the total amount of ZrB2 produced from a powder mixture of stoichiometric ratio was more than 60 %. The porosity dropped with increasing sintering temperature to a final value of about 0.3 %. The number of pore sections per square unit dropped with the temperature as well. The final product is composed of very hard as well as rather soft components.