Abrasive wear behavior of a Si3N4-MoSi2 composite

MoSi2 particles (20 vol%) have been added to Si3N4 to form ceramic matrix-intermetallic composites. Benefits associated with the addition of the MoSi2 to Si3N4 include higher strength, higher fracture toughness, no loss in oxidation resistance, and lower electrical resistivity. However, because the hardness of MoSi2 is approximately half that of Si3N4, a decrease in the specific wear rate of the Si-3-N-4-20 vol% MoSi2 composite is expected to result from the incorporation of the MoSi2 into the Si3N4. In this U.S. Bureau of Mines and Los Alamos National Laboratory study, it is found, however, that the specific wear rate of the composite during two-body abrasion by SiC particles is equivalent in magnitude to the specific wear rate of monolithic Si3N4. The specific wear rates of both the Si3N4-20 vol% MoSi2 composites and monolithic Si3N4 are four to five times less than that of monolithic MoSi2.