銀接点の接触抵抗の異常増加現象について

抄録

As the electrical contact resistance of silver is usually very small and the contact maintains a good condition, silver contact is widely used. Silver is scarcely oxidized in ordinary atmosphere, but easily sulphurized in the atmosphere containing sulphide gas whereby the contact resistance be. comes very large. In good atmosphere containing no sulphide gas the contact resistance does not increase greatly. In an experiment, howerver, many contact pieces failed in ordinary atmos-phere when they were used for impulse relay. The cause of poor contact did not seem to be the sulphurized layer because the other similar contacts in the same room were not sulphurized.
Investigation on the cause of poor contact was made by several methods. It is now clear that the cause is the sticking of dust, especially SiO₂ on the contacts SiO₂ gives rise to a non-conductive layer by the heat of discharge.