Evaluation of Mechanical Properties of Sintered Alumina with Recycling Powder

Recycling alumina powder was used to prepare sintered alumina. Virgin alumina samples were fabricated by atmospheric sintering and were crushed into powder under 500 μm in grain size by thermal shock treatment and automatic mortar crushing. Then, the crushed alumina powder was mixed with virgin alumina powder and was subjected to re-sintering to renewed alumina. The renewed alumina samples were subjected to four-point bending test and SEM observation of microstructure. Relative density and bending strength of renewed alumina decreased as the volume fraction of recycled alumina powder increased. Samples over 200 MPa of average bending strength, however, were obtained by mixing 50 vol% recycled alumina powder with grain size