TRANSIENT AND STEADY-STATE EROSION OF IN SITU-REINFORCED SI3N4

Relative to most other materials, silicon nitride is very erosion resi stant. However, the resulting surface flaws degrade strength-a serious concern component designers. An in situ reinforced silicon nitride, G S-44, was eroded in a slinger apparatus. Both transient (extremely low level) and steady-state erosion regimes were investigated. Alumina pa rticles with effective average diameters of 140 mu m and 63 mu m were used at velocities of 50, 100, and 138 m/s. The biaxial tensile streng th of the eroded specimens was measured. The strength decreased by abo ut 15 percent after a very small erodent dosage and then remained virt ually constant with further erosion.