Abrasion is a wear mechanism that is caused by the inclusion of hard particles between two sliding or rolling surfaces. Abrasion or abrasive wear leads to material removal by two mechanisms, namely two-body abrasion or three-body abrasion.
In two body abrasion the hard material are stuck in the softer surface and plough through the other, an example is shown in the image, notice the parallel lines/grooves. A classic example is the use of ‘sand’ paper, here silica particles are stuck on soft paper and used to remove material from another surface.
The three-body abrasion mechanism involves the free movement of the abrasive particles and this leads to many indents as the hard particles are pushed into the surfaces, here the material removal mechanism is more fatigue type process where the indentation process leads to work hardening and subsequent crack initiation and propagation.
Abrasion is important in many industries, where particulates are handled, such as oil and gas.