Investigation of contact surfaces and protective gas atmosphere in reed switches

M. Murko-Jezovšek, B. Praček, F. Brecelj, L. Nagy

Research output: Article

3 Citations (Scopus)

Abstract

Investigations of contact surfaces in reed switches with AES and SEM/EMP showed unwanted contamination spots, consisting of carbon or carbonaceous compounds, appearing on contacts of Au plated FeNiCo alloy after electrical loading. Protective gas from reed switches was analysed with gas chromarography (GC). Besides N2 and H2, with which reed switches had been filled with originally, the presence of impurity gases: CH4, CO, CO2, C2H4 and C2H6 with partial volumes in the range of 0.005 to 0.03 NTP μl per switch were also established. To determine their origin, contact reeds after different steps of their production run were sealed in reed switches, i.e. after preglazing, after gold plating and after thermal diffusion. Impurity gas concentration was the highest in switches with contact reeds having gold coating in as deposited state. Similarly EMP analysis of these contact reeds showed the highest surface carbon concentration. Some of these impurity gases originating from dissolved and adsorbed impurities in Au coating, kovar and glass, being released or formed in reactions with H2 during the sealing process are thermally decomposed when contacts operate under electrical load.

Original languageEnglish
Pages (from-to)1756-1758
Number of pages3
JournalVacuum
Volume41
Issue number7-9
DOIs
Publication statusPublished - 1990

    Fingerprint

ASJC Scopus subject areas

  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films

Cite this