Electrodeposition of Ni/Au composite coatings under effect of UV and X-ray radiation

The results of the study of the effect of X-rays (0.07 nm) and UV (207 nm) radiation on the rate of electrodeposition, structure and mechanical properties of composite Ni/Au coatings have been electrodeposited from electrolytes containing gold nanoparticles are presented. In carrying out research it was found that the effect of UV and X-ray radiation on the electrodeposition process of the Ni/Au composite coatings leads to an increase in the mass gain per unit area and the rate of growth of coatings due to an increase in the flux of diffusing ions of reduced metals to the cathode and also promotes to the formation of compact composite coatings. The dependencies of the mass gains of coatings over the current density are established. It is shown that mass gain-current density curves permanent increase with an increase in the current density. The dependencies of the microhardness of Ni/Au composite coatings effected with X-rays and UV radiation over the current density of deposition have been obtained. It is established that microhardness of the Ni/Au coatings increases with an increase in the current density of deposition. This phenomenon is caused by the formation of a dispersed structure of composite coatings under irradiation. Analysis of the microhardness-current density of deposition curves shows that exposure with X-ray radiation (0.07 nm) and UV radiation (207 nm) of electrolytes during electrodeposition of Ni/Au composite coatings leads to the formation of the coatings with increased hardness compare with non-irradiated samples. An increase in the microhardness of the irradiated Ni/Au coatings is associated with their density which depends on the crystallization modes and the quantity of nanoparticles in the coating. (authors)