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Wear of Surfaces and Functional Components

According to a recent study, the wear of surfaces and functional components costs developed economies about 3% of GDP. There is, therefore, a significant economic driver for the mitigation of wear. This is evidenced by the high level of ongoing innovation in the field of tribology and surface engineering, including surfacing and coatings.

The economic impact and the technological diversity of wear can be illustrated by way of example:

  • The wear of hip implants in physically active people leads to the need for more hip replacements and hence higher medical costs
  • The wear of rolls and guides in the textile and paper industries has led to the development of oxide ceramic coatings that are wear resistant and yet do not fray fine yarns or damage smooth paper finishes
  • The need for wear-resistant low friction surfaces in hot gas environments where there is no lubrication (such as piston rings) has led to the development of a variety of surface engineering solutions, including novel coatings
  • Pumps and valves carrying abrasive fluids can be protected from wear by the appropriate use of HVOF coatings or weld hardfacings

TWI is involved in research projects in the field of tribology and surface engineering, including surfacing and coatings to combat wear.

TWI can assist industry by analysing wear-related component failures and can also recommend suitable approaches to combating wear at the design stage.

The main wear processes are as follows:

  • Abrasion: includes two-body abrasion and three-body abrasion
  • Erosion: includes erosion by liquids or solid particles. The angle of attack is very important in erosion, as are the characteristics of the impinging particles (hardness, size range, speed)
  • Metal-to-metal wear: this involves adhesive wear, i.e. the micro-welding of surface asperities to one another and can lead to galling or fretting
  • Surface fatigue: this occurs when repeated strain at or just below the surface leads to micro-crack initiation and growth, leading to eventual material loss
  • Cavitation: a form of surface fatigue caused by the collapse of bubbles in a liquid and the resultant shock waves impinging on the surface of a material.

We can also offer our members access to a wide variety of wear testing facilities through our partnership with nCATS.

For more information, please email

For more information please email: