Electroplating of Chromium Incorporating High-Dispersion Black Carbon Particles

Abstract

Electrochemical composite coatings allow successfully solving many practical problems of surface-hardening of structural parts and their tooling components, as well as renewing their fast-wearing components. Electrochemical chromium-matrix composite coatings are used to enhance the thermal and wear resistance of steel articles and parts operating in friction conditions and under increased temperatures, but under low shock loads. This paper presents the results obtained from studying how fine black carbon particles affect the properties of composite coatings. Optimal conditions are found for producing high-quality coatings, such as the suspended electrolyte mixing rate and graphite concentration in electrolyte. We have also studied how heat treatment affects the microhardness and surface morphology of coatings. High-dispersed black graphite can be used to produce chromium-matrix composite coatings having increased microhardness and wear resistance.

Specific Morphological Features of the Surface of Chromium Coatings Obtained in Electrolytes with Organic Additives

“…In our investigations, a certain influence of organic additives on the adsorption processes is observed, in particular on the level of the formation of a cathode film consisting mainly of oxidehydroxide compounds. They are able to be a part of the composition of deposits as it is shown in the works [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20], and thereby to determine the qualitative characteristics of chromium coatings. In order to determine the degree of the chromium deposit contamination, the content of gases in it was investigated, given that the oxygen content is proportional to the concentration of oxide and hydroxide compounds in the deposit.…”