Optical and mechanical characterization of transparent α-alumina fabricated by spark plasma sintering

The aim of this work was the analysis of the experimental results of a transparent alumina (BMA15) ceramic which was fabricated by Spark Plasma Sintering (SPS) from nanopowder (BMA15, Baikowski Chimie, France), at different temperatures (1200 degrees C, 1250 degrees C, 1300 degrees C). With the application of a maximum uniaxial pressure of 73 MPa during all the fabrication-cycle (more than 3 hours). We sought an optimal sintering temperature combining better optical and mechanical properties of our pellets. The sintered alumina (BMA15) has a crystalline and dense microstructure. The samples sintered at 1200 degrees C exhibit the best optical properties, in particular: good real inline transmission (RIT) and an optical gap greater than those of the samples sintered at 1250 degrees C and 1300 degrees C. Due to their low density, the Young modulus of alumina sintered at 1200 degrees C, deduced by ultrasound, has a low value which is about 385 GPa. Similarly, its small grain size gives it a better Vickers hardness similar to 21 GPa. Therefore, the value of the coefficient of friction mu stabilizes around the mean value of 0.21.