Low-voltage electrical appliances play an important role in ensuring the control of energy processes, protection and switching of electrical circuits. Problems that occur in low-voltage electrical devices at rated currents of 32 - 1000 A, relate to electrical contacts that determine the operation of electrical devices. The main contribution to the development of erosion of the working surface is made by an electric arc, which is formed in the inter-contact gap when opening electrical contacts.

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... n world practice, existing solutions to increase the arc resistance of electrical contacts do not completely solve the problem of reducing erosion of their work surface. The use of additional devices in arc suppression systems leads to an increase in the size of electrical devices. The use of expensive and toxic elements in the compositions leads to an increase in the cost of electrical appliances and poisoning of the environment. Strengthening the composition of the contacts through the use of refractory elements leads to an increase in the transient resistance. The aim of the study was to substantiate and develop the main provisions of the theory of processes and phenomena that occur on the work surface and in the electrode areas of electrical contacts, and to create compositions of high arc contact compositions for switching electrical devices. The theory of the mechanism of movement of arc reference points on the working surface of electrical contacts is substantiated and the factors providing increased arc resistance due to thermoemission properties of contact composition compositions that control diffusion, migration and phase transformations during chemical reactions are obtained. It has been experimentally established and theoretically confirmed that electric erosion is mainly determined by the microstructure of the material and the change in the physical and mechanical properties of the ingredients on the working surface of the contact parts during current switching. Key words: anode, cathode, erosion, contact wear, working surface, arc column, arc resistance, transient resistance