Slip casting and sintering of Ti-doped nanosized alumina

The sintering of a nanosized gamma alumina powder has been investigated at two levels of Ti doping (0.25 and 1.5 %wt). the effect of attrition milling on the sintering of slip cast samples has also been investigated. The Ti doping has a great effect on the densfication of the unmilled powders increasing densities from around 60 to 97%. The microstructures show significant abnormal grain growth, with grain sizes ranging from 1 to 50 mum. The residual porosity is both inter and intragranular. The attrition milled samples showed similar sintered densities for doped and undoped samples 97% to 99%). When doped with Ti sintered densities were very similar for all samples around 97% indicating that the increased grain boundary mobility induced with Ti doping dominates the densification process, The doped attrition milled samples showed more homogeneous grain sizes and lower intra-granular porosity particularly for the higher dopant concentrations. The above results are presented along with dilatometry measurements and a discussion of how the accelerated sintering on Ti doping may be best utilised in the sintering of nanosized gamma aluminas.