Developments in functional surfaces for electrical contacts [Holm Award paper]

Electrical contacts have a major importance in electrical systems and despite a large quantity of work performed to improve their reliability; they can be the cause of failure. Mitigating the degradation mechanisms leading to dysfunctions of systems is a challenge that can be considered using surface engineering. Changing the properties of the surface of materials can be done in various ways. We are considering here coatings made from organic molecules because they can offer low friction, relatively low price and easy deposition process. Several types of films are considered from liquid lubricants to solid ones either free or bonded to the substrates; the behaviours of mixed and composites films are also described. Their friction, wear and corrosion properties are described as well as their conduction properties since these are often contradictory. The main problem is the conduction of such films and their role in particle debris circulation; the merit of each type of film is assed from both from an academic point of view and a practical one