Abstract Solid-particle erosion tests were conducted on hardened AISI 440C stainless steel and a cermet that consisted of ≈90 vol.% submicrometer WC embedded in ≈10 vol.% Co. Angular Al 2O 3 abrasives were used as the erodent. Experimental variables were: angle of impact = 20°, 50°, or 90°; erodent velocity = 60 or 120 m/s; erodent nominal diameter = 63 or 143 μm. For all test conditions, the stainless steel eroded faster than the cermet. Analysis of weight-loss data and examination of eroded surfaces by scanning electron microscopy indicated that the erosion mechanisms were similar for the two hard materials. Both exhibited significant plasticity when impacted, but the stainless steel's response to impact appeared to have been more ductile in nature.