Effect of TiO2–SiO2 on microstructure and mechanical characteristics of zirconium corundum abrasives by sol-gel method

Zirconium-toughened-alumina (ZTA) corundum abrasives were successfully fabricated with TiO₂–SiO₂ co-doping by using the sol-gel method. Single particle compressive strength of the obtained ZTA corundum abrasive was evaluated upon the addition of TiO₂–SiO₂ in different amounts. The effect of TiO₂–SiO₂ content on the microstructure of the product was investigated. The X-ray diffraction (XRD) results illustrated that ZrO₂ is present in the α-Al₂O₃ matrix in the form of t-ZrO₂. Ti₂ZrO₆ starts forming when the composition of TiO₂–SiO₂ is 2 wt% and increases with its addition. The sample doped with 3 wt% TiO₂–SiO₂ possessed a maximum single particle compressive strength of 45.5 N and a narrow grain size distribution,but excessive TiO₂–SiO₂ (>3 wt%) causes an abnormal grain growth. The fracture toughness of the composites dramatically increases up to 7.89 Mpa·m^1/2 compared to the monolithic. A crack closure was obviously observed in the ZTA abrasives. The influence of the second phase on its mechanical properties was analyzed.