Direct microwave sintering of yttria-stabilized zirconia at 2•45 GHz

The feasibility of using direct MW heating-with 2.45 GHz radiation distributed in multimode applicators-for the obtainment of uncracked fully dense zirconia ceramics was studied. It was found that such a sintering approach can be used in the case of ZrO2(Y2O3) powder compacts. Suitable correlation between target load mass, heating chamber architecture and forward power profile is the key to direct MW heating without thermal runaway. Sintered bulk densities close to the theoretical were obtained after,firing cycles of about 2 h. Sintering rate enhancement in the MW furnace resulted in a reduction of similar to 100 degrees C in the minimal temperature required for full densification. Mechanical properties of MW and conventionally sintered specimens (fully dense state) were not significantly different. (C) 1999 Elsevier Science Limited. All rights reserved.