Abrasive wear

Wear is the damaging, gradual removal or deformation of material at solid surfaces. Causes of wear can be mechanical (e.g., erosion) or chemical (e.g., corrosion). The study of wear and related processes is referred to as tribology.

Wear in machine elements, together with other processes such as fatigue and creep, causes functional surfaces to degrade, eventually leading to material failure or loss of functionality. Thus, wear has large economic relevance as first outlined in the Jost Report.

Wear of metals occurs by plastic displacement of surface and near-surface material and by detachment of particles that form wear debris. The particle size may vary from millimeters to nanometers. This process may occur by contact with other metals, nonmetallic solids, flowing liquids, solid particles or liquid droplets entrained in flowing gasses.

The wear rate is affected by factors such as type of loading (e.g., impact, static, dynamic), type of motion (e.g., sliding, rolling), and temperature. Depending on the tribosystem, different wear types and wear mechanisms can be observed.

Wear is commonly classified according to so-called wear types, which occur in isolation or complex interaction. Common types of wear include:

Other, less common types of wear are impact-, cavitation- and diffusive wear.

Each wear type is caused by one or more wear mechanisms. For example, the primary wear mechanism of adhesive wear is adhesion. Wear mechanisms and/or sub-mechanisms frequently overlap and occur in a synergistic manner, producing a greater rate of wear than the sum of the individual wear mechanisms.

Adhesive wear can be found between surfaces during frictional contact and generally refers to unwanted displacement and attachment of wear debris and material compounds from one surface to another. Two adhesive wear types can be distinguished:

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