Wear characteristics of Si3N4/SiC composite ceramics with added SiO2 colloid

This study analyzed the wear characterization of Si3N4 ceramics according to the different amount of added SiO2 nano colloid. Test specimens were made by hot-press sintering at 35 MPa, 2123 K in N-2 gas for 1 h. The wear tests were performed with a block on ring tester. The test conditions were as follows; (1) rotation speed of ring which has a 35 mm diameter was 50 rpm; (2) load was 9.8 N; and (3) the temperature was 25 degrees C. The test results show that Si3N4 ceramics have a wear coefficient of about 1.0 and wear loss about 0.02 mm. Among the specimens used in this study, the test specimen with 1.3 wt.% SiO2 nano colloid added gave the best wear resistance because of its lowest wear coefficient and its smallest wear loss. In addition, this specimen showed the highest Vickers hardness and bending strength. The wear coefficient was in inverse relation to the hardness and bending strength.