Sintering Of MgO and TiO2 Doped Al-Zr Oxides Composites by Extended Arc Thermal Plasma

Abstract

MgO and TiO2 doped Al-Zr oxide composites of Zr0.95Al1.05MgxO with x=0,0.01,...,0.05,0.75,1 and Zr-0.95-Al-1.05-Ti-z-O with z=0, 0.025,..., 1 were sintered to high density by both DC thermal plasma assisted rapid sintering as well as conventional sintering. It is observed that the above mentioned MgO and TiO2 doped Al-Zr oxide composites were sintered to high density end products by the thermal plasma heating technique within a short sintering little (a few minutes) as compared to a conventional long range resistive heating schedule (a few tens of hours). It is also noticed that there exists a critical limiting point of MgO doping concentration (x=0.05 in Zr0.95Al1.05MgxO) for maximum physical densification in both conventional as well as plasma sintered samples. Sintered specimens were analyzed by XRD studies. XRD studies revealed the presence of a high density phase, Mg2Zr5O12 prominently in x=0.05 sintered sample which resulted in maximum densification of the sample. With increasing doping concentration of TiO2 (i.e. z=0 to 1), rho(s) (sintered density) of both plasma sintered and conventional sintered specimens were found to follow a concavity like variation with well defined critical limit of TiO2 concentration (i.e. at z=0.05) at which rho(s) became minimum. However, hardness was found to be maximum at z=0.05.