Rezumat
CZU 669.2.017:620.17; 669.2.017:620.18
https://doi.org/10.52577/eom.2024.60.2.31
The results of the studies of electrical modes of the high-frequency high-voltage plasma electrolytic oxidation (PEO) on the properties of the formed protective coatings on the B95 T1 and D16ч T aluminum alloys are presented. The control of the PEO process was carried out by changing the amplitude values of anode and cathode voltage pulses. The local mechanical characteristics and the structure of the PEO coatings were studied using instrumentedindentation and scanning electron microscopy. As a result of the studies, optimal modes of the PEO process were determined: potentiodynamic modes with a smooth decrease in the amplitude of anode voltage pulses at a speed of 5 V/min and a smooth increase in the amplitude of cathode voltage pulses at a speed of 1 V/min. The coatings formed in the optimal modes of the PEO were characterized by a reduced number of defects (microcracks, craters, pores) and high values of hardness of 27.5–27.8 GPa and elastic modulus of 286–309 GPa averaged over their thickness. These characteristics turned out to be higher by 33–45% and 15–30%, respectively, compared with a hardness and elastic modulus of the coatings, formed in other studied PEO modes.
Keywords: plasma electrolytic oxidation, electrical modes of plasma electrolytic oxidation, oxide ceramic protective coatings, aluminum alloys, scanning electron microscopy, instrumented indentation, local mechanical properties.