Abstract Plasma electrolytic oxidation (PEO), a promising surface treatment method to improve the corrosion and wear resistance of magnesium and its alloys, operates at high voltages, resulting in a relatively high energy cost. To make the PEO process more economically viable, its energy efficiency needs to be improved. This study investigates the growth behaviour and microstructural characteristics of low-energy PEO coatings on an AM50 magnesium alloy in a concentrated electrolyte containing so...
The role of MgH2 in the process of filiform-like corrosion on Mg alloys has been investigated. MgH2 was grown galvanostatically on the Mg ZEK100 alloy at a current density of -5 mA/cm2 for various times in 0.1 M NaOH and the subsequent electrochemical and corrosion behaviour compared to that of as-polished specimens. Polarization curves demonstrated cathodic activity under anodic polarization (i.e., the ânegative difference effectâ) while XRD confirmed the presence of MgH2. Dynamic SIMS meas...
Abstract Plasma electrolytic oxidation (PEO) coatings were grown on an aluminium alloy substrate using different processing parameters which enabled samples to be coated to different stages of the PEO process. Electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques were employed to investigate the impedance properties of the resulting oxide coatings which will determine the corrosion performance of the coated alloy. Scanning electron microscopy was used t...
Abstract Alumina coatings were deposited on 6061 aluminum alloy substrates using plasma electrolytic oxidation (PEO) in an alkaline silicate electrolyte. Different electrical parameters, including frequency, duty cycle, and current density were applied to obtain PEO coatings. Scanning electron microscopy (SEM) and microhardness tests were used to investigate the coating microstructure and properties. For each sample, the voltage–time response of the PEO process was obtained and compared with sur...
The reuse of industrial wastes from a coal-fired power plant and a plasma electrolytic oxidation process was attempted to realize a zero discharge. The batch composition was adjusted by adding sodium hydroxide and sodium aluminate. A single-mode microwave oven equipped with reflux condenser was used for crystallization under atmospheric pressure. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, BET, thermogravimetric analysis, and cation-exchange cap...
Abstract Oxide coatings were produced on a 6061 aluminum alloy using a pulsed unipolar plasma electrolytic oxidation (PEO) process. The effect of electrical parameters including pulse frequency, duty cycle and current density on phase formation in the coatings was revealed using conventional and glancing angle X-ray diffraction. The results show that PEO coatings are mainly composed of γ-Al 2 O 3 . Depending on the electrical parameters employed, the coatings can also contain α-Al 2 O 3 and mull...
Abstract Ceramic coatings were created on the surface of 6061 aluminum alloy using a plasma electrolytic oxidation (PEO) process employing a pulsed direct current (DC) power mode in an alkaline electrolyte. The effect of electrical parameters including frequency and duty cycle on the microdischarge behavior and coating growth was investigated at constant current. Surface features of coatings were studied using scanning electron microscopy. Energy dispersive spectroscopy was employed to investiga...