Failure mechanisms in stationary low current contacts

The purpose of this paper is to highlight the ways in which stationary low current contacts can fail. It begins by describing the various categories of components that the term ´contact´ embraces and gives a few simple definitions in order to qualify the analysis. The main section focuses in on individual failure mechanisms and describes them in more detail. In order to provide a coherent analysis the various mechanisms have been groups into broad bands. At the highest level these are ´chemical´ and ´mechanical´ and refer to the prime effect of a particular mechanism. These have then been divided and sub-divided until at the lowest level the individual mechanisms are given. In this way a tree type structure is formed, giving a hierarchy of failure mechanisms. This also helps to illustrate their interdependence. It is hoped that this paper will act as a review to new readers to the subject. While no area has been analysed in great detail, a suitable reference list has been included for those readers who wish to examine specific topics in more depth.<>