Fabrication of ZrO ₂ toughened Al ₂O ₃ ceramic through gelcasting process

ZTA(Zirconia toughened alumina)composite ceramics were prepared using a low-toxicity monomer N, N-dimethyl acrylamide(DMAA), mass ratio of Al ₂O ₃ to ZrO ₂ is 3:1, the solid loading of suspension is 50 vol%. The effect of dehydration mode on the dehydration rate and property of green body were discussed. The effect of different polymerize temperature to the strength of green bodies were investigated. The result show that the green bodies dried in moist heat oven had the highest strength and the polymerize temperature should be hold on about 65°C. The properties of ZTA ceramics sintered with green bodies of different DMAA content had been compared, and the best DMAA content was 10wt%. By contrasting the mechanical properties of sintered bodies made by gelcasting and dry pressing, the bending strength and fracture toughness of the ceramics made by gelcasting increased about 42.2% and 23.5% than dry pressing, reaching 640 MPa and 6.3 MPa· m ^1/2, respectively. SEM images show that ceramics made by gelcasting have more uniform microstructure than dry pressing.