Effects of Sm_(2)O_(3) addition on sintering behavior of pre-synthesized magnesia-rich magnesium aluminate spinel

The effects of Sm_(2) O_(3) as an additive on the densification of a pre-synthesized magnesia-rich spinel were investigated.The sintering behavior of the material was characterized by analyzing its dilatometric characteristics,linear shrinkage,bulk density,apparent porosity,phase structure,and micro structure.Moreover,the cold modulus of rupture(CMOR) and microhardness of the spinel were measured.The results show that samarium oxide reacts with the spinel to form SmAlO_(3)(a rare-earth aluminate) to improve the sintering performance and mechanical properties of the spinel. The formation of magnesite phases decreases the rupture strength of the spinel.However,this MgO phase is inlaid in spinel grains boundary,has a pinning effect which can improve the sinterability of the spinel.