Original scientific paper
Influence of decomposition of carbon containing gases on contact resistance of reed switches
Miran Mozetič
; Institute of Electronic and Vacuum Technique, Teslova 30, 61000 Ljubljana, Slovenia
Melita Murko-Jezovšek
; Institute of Electronic and Vacuum Technique, Teslova 30, 61000 Ljubljana, Slovenia
Tomo Bogataj
; Institute of Electronic and Vacuum Technique, Teslova 30, 61000 Ljubljana, Slovenia
Abstract
During the operation of reed switches, a continuous increase of the contact resistance was observed. After the life time test, AES analyses of the contact surfaces showed an appearance of carbon, which originally wasn't present. In order to find the origin of carbon on the surface, model reed switches were prepared, evacuated, and than filled with a protective gas with intentionally added carbon containing gases. After the lifetime test of the reed switch models, the contact resistance of switches filled with N2 + H2 , N2 + H2 + CO and N2 + H2 + CO +CO2 remained low while the resistance of switches filled with N2 +CO + CO2 and N2 +H2 + C2H2 increased substantially. AES analyses have shown that the quantity of carbon deposited on contacts of switches filled with N2 + H2 + C2H2 was much greater than that deposited on contacts of switches filled with the other gases. Since gas chromatographic analysis showed an appreciable lowering of the C2H2 concentration, we concluded that C2 H2 decomposed on the contact surfaces causing the increase of the contact resistance.
Keywords
Hrčak ID:
299599
URI
Publication date:
2.5.1996.
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