Effects of Pressure Application Method on Transparency of Spark Plasma Sintered Alumina

Commercially available alumina powder was consolidated at 1150 degrees C by spark plasma sintering at the heating rate of 100 degrees C/min. The effects of the pressure application mode were examined with respect to microstructure, porosity, and transparency. A finite-element simulation was developed in order to understand the relationship between sample homogeneity and its temperature distribution. The effects of the temperature probing point on the microstructure were investigated. The application of two steps pressure was found effective to obtain homogeneously densified translucent alumina samples at high heating rate.