Is there a No-Effect Level (NEL) for adverse effects on electromechanical components by volatile siloxanes?

Emissions from silicone elastomers, used as seals and adhesives, may impair the function of electrical contact surfaces in electromechanical components, a phenomenon that has been known for a long time. At the same time, the automotive industry heavily relies on the very good properties of silicones. Hence, a detailed risk assessment is necessary when using silicones. Therefore, we investigated the reliability of a relays when operated in a siloxane gas atmosphere. To elucidate failure mechanisms, the failed relays were analysed by optical microscopy, SEM, EDX and FIBS. In the reliability experiments, the siloxane concentration and type, current strength, humidity and temperature were varied to evaluate their specificimpact. The overall aim was to search for a No- Effect Level (NEL) below which there is no negative impact on the service life of the relay.