Effect of Sintering Additive Composition on the Mechanical and Tribological Properties of Si$lt;inf$gt;3$lt;/inf$gt;N$lt;inf$gt;4$lt;/inf$gt;/SiC Ceramics

Two compositions of the Y 2 O 3 -Al 2 O 3 (YA) and Y 2 O 3 -MgO (YM) systems were chosen to investigate the effect of sintering additive composition on the mechanical and tribological properties of gas pressure sintered Si 3 N 4 /SiC ceramics. The relative density, flexural strength, fracture toughness, hardness, coefficient of friction and wear rate were verified to depend substantially on the sintering additive composition. Compared with YM, the Si 3 N 4 /SiC ceramics with YA exhibit superior sinterability and show preferable mechanical and tribological properties, especially for the Si 3 N 4 /SiC ceramics with 20wt% SiC addition. These properties can be primarily attributed to the higher relative density and the grain size with smaller aspect ratio.