Effect of SPS Sintering Temperature on Properties of ZrB₂-SiC Ceramic

Abstract

Two ZrB2-20% (volume fraction) SiC(ZS) ceramics were sintered successfully by spark plasma sintering (SPS) process at 1700 ℃ and 1900 ℃ respectively. The SEM, EDS, hardness, fracture toughness, bending strength, mass gain and cross section of oxidized ceramics were analyzed to investigate the effect of sintering temperature on microstructure, mechanical properties and oxidation resistance of ZS ceramic. The results show that the grain size and relative density of ZS ceramic are increased with the increase of sintering temperature. When the sintering temperature is raised from 1700 ℃ to 1900 ℃, the density increases from 98% to 99.8% and the hardness increases from 12.6 GPa to 14.7 GPa. With the increase of sintering temperature form 1700 ℃to 1900 ℃, the bending strength at 1600 ℃ increases from 101 MPa to 286 MPa, and the bending strength at 1800 ℃ increases from 138 MPa to 302 MPa. The oxidation behaviours of the two ceramics at 1500 ℃ in air are also investigated. The oxidation depth of ZS ceramic sintered at 1900 ℃ is smaller, and the infiltration of O into the substrate is less, which indicates that the oxidation resistance of ZS ceramic sintered at 1900 ℃ is improved.

Keywords

• ceramic
• spark?plasma?sintering(SPS)
• ZrB₂-SiC
• sintering temperature