Impact abrasion. Our present knowledge concerning impact abrasion is surveyed. Impact abrasion of a wall is taken to mean its destruction as a result of collisions with solid particles. The article first presents a phenomenology of abrasion based on experimental studies and observations with a scanning electron microscope. Abrasion occurs in three phases: wear, lamellation, and destruction. Based on this phenomenology the wear of planar plates is examined as a function of the principal variables, i.e. the angle of incidence of the particles, their velocity, the duration of the experiment, concentration of solids in the particle beam, and the mechanical properties of the particles and the plate. Plate abrasion, which can be determined experimentally with relative case, serves as the starting point for a consideration of wear in pipe elbows. Differential analysis of the wear of curved surfaces is employed. The paper closes with a consideration of wear in components of equipment and machinery.