The particle size effect in abrasion studied by controlled abrasive surfaces

Abstract

The effect of abrasive particle size on the wear rate is well known. For small particles the wear rate increases with increasing particle size. Above some critical size the wear rate becomes almost independent of further size increases. Several theories have been presented to explain the size effect. We have examined a theory based on the particle shape, specifically the bluntness of the abrading tips. A micro mechanical etching technique has been used to produce relatively large surfaces covered by silicon abrasive tips of extremely well defined shape, size and lateral distribution. Different particle sizes were simulated by changing the packing density. Further, were both sharp and blunt pyramidal tips produced. Wear rates were obtained by a pin on abrasive disc configuration with tin as abraded material. By using a soft material as tin as abraded material the silicon tips retained their initial shape the entire test. The results show that the wear rates are similar for ideally sharp tips of different packing densities. Hence, sharp tips exhibit no size effect. For blunt tips, however, a size effect is present. The difference between the wear rates obtained for the different packing densities is significant. These results confirm the shape theory to be valid under the test conditions used.