Carbon contamination of contacts due to organic vapors

The formation of carbon on the contact surface of commercial relays by thermal decomposition of organic vapors emanating from various organic materials may cause an undesirable increase of the contact resistance of the order of several ohms. A model switch was developed to investigate the influence of outgassing vapors of any organic material on contact reliability. Carbon deposits on contact surfaces cause certain phenomena confirming that the observed characteristic contact resistance increase to a value of the order of several ohms is caused by elementary carbon. Investigations of various organic materials showed that their contact compatibility cannot be derived just from the qualitative knowledge of their emanating vapors, but that the problem is more complex and requires a quantitative approach.<
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