PREPARATION OF ZrB₂ BY BORO/CARBOTHERMAL REDUCTION IN SPS DEVICE

Abstract

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 °C were chosen for the experiment. For example, after sintering at a temperature of 1800 °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.

Keywords

• Zirconium diboride
• Zirconia
• Boron carbide
• Borothermal reaction
• Carbothermal reaction
• Spark plasma sintering (SPS)