Laser-enhanced electrodeposition of composite nickel coatings

DOI: 10.62564/M4-VT2009

Valentyna Tytarenko

National Technical University Dnipro Polytechnic, Ukraine


The solution to the surface hardening problem is the modification of the metal matrix with particles of the dispersed phase to obtain composite electrolytic coatings [1, 2]. The purpose of this work is to study the effect of laser radiation on the process of co-deposition of metal ions and ultradispersed diamond particles, structure, mechanical and protective properties of electrodeposited composite nickel coatings. Electrodeposition of composite coatings was carried out from sulphate nickel-plating electrolyte out under external exposure to radiation from a CO2 gas-discharge laser generating in a continuous mode at a wavelength of 10,6 μm at a laser radiation power of 25 W. X-ray microanalysis was performed using a JSM-64901LV scanning electron microscope (Japan). The increase in the concentration of smaller ultradispersed diamonds (UDD) particles (~0,25–1 μm) in the coating formed under laser-assisted deposition is due to the potential gradient and rise in the diffusion coefficient. The increase in the flux density of complexes formed as a result of the adsorption of metal ions on the surfaces of UDD particles leads to an increase in oversaturation at the crystallization front. The formed coating is reached by smaller size UDD particles that block the growth of nuclei of the crystalline phase, which leads to the formation of a more densely packed coating and changes the cross-sectional growth structure from columnar to microlayer. The formation of finer crystalline coatings and change of cross-sectional growth structure from columnar to microlayer at laser-assisted deposition process resulted in improvement of mechanical and protective properties of carbon-containing nickel coatings (coating microhardness increased from 1800-1950 MPa to 2500-3700 MPa, corrosion resistance increased 2 times, and the wear of coatings decreased 3 times).

Keywords
ultradispersed diamond particles, electrodeposition, composite electrolytic coatings

Acknowledgments
Not provided

References
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