A Silver-Based Electrocontact Material Dispersion-Strengthened with Zinc, Tin, and Titanium Oxides
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ICAL SCIENCE OF MATERIALS
A Silver-Based Electrocontact Material Dispersion-Strengthened with Zinc, Tin, and Titanium Oxides G. M. Zeera,*, E. G. Zelenkovaa, A. V. Sidorakb, V. V. Beletskiia, S. V. Nikolaeva, V. V. Kolota, and M. Yu. Kuchinskiia a Siberian b
Federal University, Krasnoyarsk, 660041 Russia ОАО Krastsvetmet, Krasnoyarsk, 660027 Russia *e-mail: [email protected]
Received June 27, 2018; revised February 18, 2020; accepted February 19, 2020
Abstract—A new silver-based electrocontact material dispersion-strengthened with nanopowders of zinc, tin, and titanium oxides has been obtained. The microstructure and elemental composition of the phases formed during solid-phase sintering and electroerosive tests have been studied by electron microscopy and energydispersive microanalysis. The electroerosive wear is determined during laboratory tests, and the transition resistance is calculated. The developed electrocontact material possesses physicomechanical and operating characteristics that are similar to those of a commercial contact prepared using toxic cadmium oxide. DOI: 10.1134/S106378422008023X
INTRODUCTION Electrocontact materials should combine physicomechanical and operating characteristics such as erosion and corrosion resistance, hardness, high electric and thermal conductivities, and low transition resistance arising when closing contacts [1, 2]. Composition electrocontact silver- or copper-based materials with dispersion-strengthening and arc-suppressing powders of metals, oxides, borides, carbides, and their various combinations added to the composition of an initial mixture obtained by powder metallurgy meet these requirements [3–18]. The influence of these additives on the physicomechanical and operating characteristics is investigated when developing cadmium-free materials for electrocontacts. A popular arc-suppressing additive in the composition of commercial electrocontact materials is cadmium oxide [2]; however, it is characterized by high volatility and toxicity. Therefore, there is a necessity of replacing it with other components (for example, zinc oxide [3, 4, 6, 7, 18, 19] and tin oxide [9–15], which have similar physicochemical properties). In addition, the properties of electrocontact materials with dispersion-strengthening and arc-suppressing additives such as tin oxide or zinc oxide combined with other components (e.g., Ti, Hg, Bi, Ce, and In2O3) are currently being studied and the possibility of their application is being analyzed [1, 2, 13–17]. Wear of contacts due to mass transfer, evaporation, and sputtering of material at opening of an electric circuit (arc erosion) is caused by arc discharge; it is the main factor determining the quality of an electrocon-
tact material. Arc erosion is accompanied by interaction between solid and liquid metal with atmosphere components and arc plasma with the formation of oxides and other low-conductivity compounds. Mechanical interaction between contact surfaces occurs at separate portions, the area of which and the presence of surface films af
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