The Effect of Combinations of Carbon Nanomaterials on the Microhardness of the Chromium Galvanic Coating

A method to increase the microhardness of the chromium galvanic coating by adding a mixture of carbon nanomaterials (nanodiamonds, single-walled and multi-walled nanotubes, graphene oxide) into a standard chromium galvanic coating electrolyte was proposed. The increase in the microhardness of the chromium galvanic coating was revealed and explained. This is due to a combination of two mechanisms: the introduction of nanodiamonds into the crystal lattice of the coating metal and the appearance of additional crystallization centers on defects in carbon nanotubes. The method of obtaining parts with a higher service life when using traditional chromium galvanic coating, as well as when using multi-walled carbon nanotubes, single-walled carbon nanotubes, nanodiamonds, and graphene oxide separately, was demonstrated. The best result was obtained using a mixture of nanodiamonds and multi-walled carbon nanotubes. The microhardness of the nanomodified chromium galvanic coating was measured, and it was found to increase by 27 %.