Pressureless Sintering of TiB₂-Al₂O₃

Abstract

Sintering conditions and mechanical properties of TiB₂-Al₂O₃ composites produced by pressureless sintering at 1600° to 1900°C by using two types of TiB₂ powder with different average particle size were investigated. The content of more than 40wt% Al₂O₃ yielded the composites having relative density of more than 95%. The bending strength of the composite containing coarse TiB₂ powder and 60wt% Al₂O₃ was 300MPa. And that of the composite containing fine TiB₂ powder and 50wt% Al₂O₃ was 450MPa. The Vickers hardness of the composites were about 15GPa. The electrical resistivity increased with increasing amount of Al₂O₃ and changed drastically from about 10^-3Ω·cm to 10⁵Ω·cm for 75wt% to 95wt% addition of Al₂O₃.