Wear-Resistant and Anticorrosive Coatings Based on Chrome Carbide Cr7C3 Obtained by Electric Spark Deposition

摘要

This work is devoted to the deposition of Cr3C2 chromium carbide powder on steel 35 by electrospark treatment in titanium granules. Three mixtures of granules containing Cr3C2 powder were prepared from 7.4 to 15.6 vol %. X-ray phase analysis of coatings showed the predominance of the Cr7C3 phase, which is the product of the decarbidation of Cr3C2 chromium carbide when it interacts with the iron of the substrate. With an increase in the powder content in the mixture of granules, the microhardness of the coatings increased from 8.2 to 9.8 GPa. The average coefficient of friction of the coatings ranged from 0.42 to 0.68. The wear resistance of coatings in dry wear mode was 20-57 times higher than that of steel 35. Polarization tests of coatings in 3.5% NaCl solution showed significantly lower corrosion potential and current, and higher resistance to polarization compared to steel 35. Study of heat resistance at a temperature of 700 degrees C showed that the use of coatings on steel 35 increases the resistance of its surface to high-temperature gas corrosion by 14-18 times per 100 h of testing. The tests carried out have shown that the optimal content of Cr3C2 powder in a mixture with granules is in the range of 11.7-15.6 vol %.