SINTERING OF MGO AND MGO-TIC CERAMICS BY PLASMA, MICROWAVE AND CONVENTIONAL HEATING

The densification of MgO and MgO-TiC ceramics by hollow cathode plasma and microwave sintering techniques was studied. The resultant fractio nal densities were compared to those of conventionally sintered sample s. It was demonstrated that indirect heating and sintering of MgO by m icrowave radiation was possible. Higher fractional densities were obta ined in MgO by microwave sintering in comparison to conventional sinte ring under the same conditions. In the case of MgO-TiC composites, che mical reaction led to Mg2TiO4 formation in all samples. Plasma sinteri ng suppressed this reaction and exhibited reduced sinterability upon T iC addition. On the other hand, small amounts of TiC additions aided t he conventional sintering of MgO, resulting in better mechanical prope rties. Furthermore, commercial grade MgO was sintered to higher densit ies than relatively pure research grade MgO. Hardness and fracture tou ghness values are reported.