Preparation of wear‐resistant ceramic coating by dynamically controlling the resistance during MAO

Abstract Micro arc oxidation (MAO) is a surface treatment technology that typically involves immersing the valve metal in an electrolyte to generate a ceramic coating for improved surface characteristics. This paper proposes a novel MAO g48 the need for electrolyte immersion. The MAO power supply's positive electrode is connected to the valve metal as the anode, while the negative electrode is connected to a stainless‐steel wire in the electrolyte circulation system. The distance between the cathode and anode is dynamically adjusted using a mechanical arm. Through advanced techniques like X‐ray diffraction and X‐ray photoelectron spectroscopy, successful ceramic coatings comprising α‐Al ₂ O ₃ and γ‐Al ₂ O ₃ phases on aluminum substrates were achieved. Tribological experiments demonstrated that coatings prepared with a cathode‐anode distance of 1.0 cm exhibited a scratch width of approximately 286.160 μm, while a distance of 3.0 cm resulted in approximately 1736.80 μm. This highlights the significant impact of the cathode‐anode distance on the wear resistance of the plasma electrolytic oxidation ceramic coating, with optimal performance observed at 1.0 cm. Utilizing a robotic arm to control the cathode movement enables effective surface treatment of large workpieces and targeted regions, addressing practical challenges in MAO applications.