ABSTRACTThe steady-state solid particle erosion behavior of hot-pressed Si3N4 reinforced with 0, 10, and 20 weight percent SiC whiskers has been investigated at room temperature using angular alumina particles (63 to 270 μm diameter) as the erodent. The impact angle was varied from 30 to 90 ° and particle velocities were varied from 80 to 140 m/s. These materials were found to be very erosion resistant. However, there was little effect of the SiC whisker reinforcement on either the absolute erosion rate or on the velocity or particle-size exponents for the rates.The lack of a fiber reinforcement effect occurs even though the fiber additions provide an increase in the fracture toughness at high fiber contents. Results on differently processed Si3Na4 .base materials showed that microstructural variations due to processing history have very significant influence on the erosion resistance of the base (matrix) material. The results substantiate the idea that microstructure plays an important, but not fully understood role in the erosion processes for brittle materials.