Investigations of selected mechanical, wear properties and transparency of alumina obtained by combined PIM and SPS techniques

To produce transparent alumina pieces, alpha-alumina nanoparticles with different amounts of MgO sintering aid were dispersed in a paraffin-polypropylene-based binder system. The alumina-binder feedstock was optimized for the powder injection molding (PIM) method. After binder removal, the green body piece was sintered through the spark plasma sintering method. Rheometric tests, Vickers measurement, three-point bending flexural test, and Archimedes test were used for the feed fluidity, hardness, flexural strength, and density of the sintered pieces, respectively. Next, IR and visible transmission of SPSed bodies were measured. The results showed that a combination of PIM and SPS methods with 500 ppm sintering aid causes higher IR and visible transmission than the sample with 600 ppm sintering aid. In addition, the hardness of as-obtained transparent alumina was in the range of 16-16.5 GPa. The flexural strength of the as-obtained transparent sample (with 500 ppm MgO) was more than SPSed with 600 ppm MgO sintering aid.