Influence of TiN addition on densification behavior and mechanical properties of ZrB2 ceramics

Abstract

In the present work, densification behavior and mechanical features (fracture toughness and Vickers hardness) of undoped and TiN-doped ZrB₂ ceramic materials, hot-pressed at 1800 ºC under 15 MPa for 1 hr, were studied. The addition of only 5 wt% TiN into ZrB₂ has resulted in an increase in its relative density from 83% to 90 %. Removal of oxide contaminations like B₂O₃ via chemical reactions with TiN and new secondary phases formation such as ZrN, h-BN, and (Zr,Ti)B₂ solid solutions were approved employing crystalline phase analysis and microstructural studies. Improvement of densification and restriction of grain growth caused enhancement of mechanical characteristics. The measured values of Vickers hardness and fracture toughness are ameliorated from 7.8 GPa and 1.5 MPa.m^1/2 to 14.1 GPa and 3.8 MPa.m^1/2, respectively.