Analysis Of Electrical Contact Materials Reliability

Application of electrical contact is a very broad range of disciplines, with development of science and technology, equipment requirements of various instruments also increasing, thus the reliability of electrical contact materials, become more and more important. China is a more serious pollution country, and because contacts are mostly exposed to the environment, so that environmental pollution is is one of the main reasons that caused electrical contact failure.This experiment was prepared three types of electrical contact materials by powder metallurgy, AgSnO₂, AgWC,AgSnO₂CeO₂, and test corrosion characteristics of the three kinds of materials under SO₂ gas and simulated sea water environment and the corrosion mechanism of Various materials in different environments was studied and discussed.It is found that under SO₂ corrosion conditions, AgWC do well both in mechanical and electrical contact properties; while the AgSnO₂ which added CeO₂ can significantly improve the mechanical properties as well as anti- Welding and arc capacity,although the conductivity have a slightly decrease in performance,it is more suitable for the conditions of high temperature and high load. In the high humidity environment, as Ag SnO₂CeO₂ relatively low density materials, the surface of the water film to the substrate more easily penetrate to the organization, resulting in even more depth of corrosion, the corrosion resistance is poor, not suitable for use.In the higher humidity of the SO₂ environment, Ag has a tendency to localized corrosion, corrosion products at corrosion point is mainly formed by sulfate. SO₂ can turn the original,protective Ag₂O film on the surface into a corrosion products film which porous,loose and lack of protective.That is why SO₂ has strong destructive on the materials. Thickness of corrosion film thickening gradually with time, but because of gas reach to the metal surface through the product film to, therefore, with the increase of film thickness ,growth rate continuously decreased.AgWC by electrochemical tests in NaCl solution was found the best corrosion resistance, After addition of rare earth oxide material CeO₂,AgSnO₂'s ability of Cl^- corrosion resistance and corrosion resistance increased.It was found that due to the solution conductivity and oxygen limitation, material corrosion rate increased with the rise of concentration and then decreased, when reached 3% of the maximum that is materials has most serious corrosion in seawater compared to other concentration in the solution...