ABRASIVE WEAR BEHAVIOR OF A SI3N4-MOSI2 COMPOSITE

MoSi2 particles (20 vol%) have been added to Si3N4 to form ceramic mat rix-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. H owever, because the hardness of MoSi2 is approximately half that of Si 3N4, a decrease in the specific wear rate of the Si-3-N-4-20 vol% MoSi 2 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 L aboratory 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 specif ic wear rates of both the Si3N4-20 vol% MoSi2 composites and monolithi c Si3N4 are four to five times less than that of monolithic MoSi2.