Abstract
Alumina ceramics were densified by pulse electric current sintering (PECS) using γ-alumina powders prepared from polyhydroxoaluminum-polyvinylalcohol (PHA-PVA) composite gels at sintering dtemperatures of 1250∼1550°C. PECS conditions and optimizing of calcining temperature of PHA-PVA gels were investigated. The rapid sintering by PECS was advantageous to enhance densification in the sintering of γ-alumina powders prepared from PHA-PVA gels, resulting in specimens with a relative density of more than 99% for holding time of 3 min under uniaxial pressure of 30 MPa. The use of monophasic γ-alumina powders made the sintering temperature shift to lower temperatures. The bending strength of sintered compacts fired at 1350°C reached a value as high as about 800 MPa when the sample powders were calcined at 850∼950°C.
