A STUDY ON WEAR AND EROSION OF SIALON-SI3N4 WHISKER CERAMIC COMPOSITES

Sialon-based ceramic composite materials containing 0-20 wt.% Si3N4 wh iskers were hot pressed and their mechanical properties and microstruc tural characterization were investigated. The specimens were subjected to ball-on-reciprocating plate type wear tests at temperatures betwee n room temperature and 1073 K. A gas blast type erosion tester was emp loyed to examine erosion behavior of the composite at room temperature and 773 K. Si3N4 whiskers caused formation of large elongated grains in the microstructure. The specimen with the higher content of Si3N4 w hiskers exhibited higher fracture toughness and lower flexural strengt h resulting from the larger grain size. Wear test results showed that a higher wear rate was obtained as whisker content and test temperatur e increased. Scanning electron microscopy observation on the wear trac k of specimens containing 0 and 20 wt.% Si3N4 whiskers tested at 1073 K revealed that the one with 20 wt.% of Si3N4 whiskers had deeper groo ves inside the track than that with 0 wt.% Si3N4 whiskers. Erosion tes t results showed a tendency similar to that of the wear test results. The higher the test temperature and the more whiskers the specimen con tained, the higher the erosion rate. (C) 1997 Elsevier Science S.A.