Thermal plasma-sintered Ti-doped Al—Zr oxide composites: X-ray photoelectron spectroscopy studies

Abstract

Ti-doped Al—Zr oxide composites (Zr1− x–Al1+ x–Ti x–O y with x = 0.05, 0.1, 0.15) were sintered to high density end products by an extended arc DC thermal plasma heating technique within a short sintering time as compared with a conventional long range resistive heating schedule. Thermal plasma-sintered samples showed conducting behaviour at room temperature whereas conventional-sintered samples became highly resistive. Specimens were analysed by X-ray photoelectron spectroscopy, X-ray diffraction, and Electron Probe Micro Analyzer studies. Higher binding energy of Zr 3d lines in a plasma-sintered sample showed that ZrO2 has strongly reacted with TiO2, thereby enhancing the possibility of ZrTiO4 phase formation. The increase in Al 2p binding energy for a conventional-sintered sample indicated the reaction of Al2O3 with TiO2, which was likely to enhance Al2TiO5 phase formation. XRD and scanning electron microscope analysis along with density studies corroborated this finding. The existence of elemental Ti at 453.3 eV and the presence of TiC at 455.2 eV were found to be responsible for conducting behaviour of plasma-sintered composites.