The selection of materials for components exposed to wear situations involves a diversity of factors; a systematic approach to selection is out-lined to ensure that no significant factors are overlooked. The relation between materials properties and wear is examined and materials to avoid wear are considered; ancillary factors that influence selection are reviewed.

Satisfactory performance of surfaced components depends upon careful selection procedures, as well as good surfacing practice. After a review of available surfacing treatments and a comparison of their principal characteristics, a systematic approach to the problems of selection against wear is discussed, and the ancillary factors that must also be considered are described; design aspects are included

A great variety of surface coatings and treatments is used to combat wear and corrosion in the many types of rotary and reciprocating engines now in service. This paper is primarily concerned with the tribological behaviour of engine components, but corrosion and other problems are referred to where the different elements of functional performance are inseparable.