Abstract:The erosion wear behaviour and mechanism of several middle temperature seal coatings were investigated by a CMS-100 self-made vacuum sand erosion machine. The results show that the relationship between the erosion mass loss and the erosion time is linear, the coatings hold a maximum erosion rate at 60°  impact angle, and the relationship between the erosion rate and the impact speed is an exponential function. The speed exponent increases with the increase of the impact angle. At 90° impact, indentations and extruded lips were generated on the coating surface subjected to impact. With repetitive impact by the abrasive particles,the extruded lips were work-hardened and peeled off, while flattened metal phase grains were impacted repeatedly, loosed and debonded. At 30°  impact, the erosion wear of the coating is characterized by micro-cutting, plowing and tunneling via p ores and non-metal phase. The model of the erosion mechanism is advanced on the basis of the above-mentioned erosion wear behaviour.

Key words: abradable seal coating;erosion wear;mechanism;model