Effect of MgO micro-powder on the characteristics of micro-arc oxidation coatings

ABSTRACT

MgO micro-powder of different concentrations from 0 to 8 g L⁻¹ was added in the electrolyte. Effects of MgO micro-powder concentration on properties of micro-arc oxidation (MAO) coating were analysed by scanning electron microscopy, energy dispersive spectrometer, X-ray diffraction, electrochemical workstation, thermal shock tester equipment, etc. The result revealed that the concentration of MgO has evident effects on the properties of the MAO coating. When MgO micro-powder increased, the oxide voltage, the coating thickness and hardness increased first and then decreased. In this case, the diameter of the hole on the coating surface also increased and more linear holes appeared. The phases mainly consist of γ-Al₂O₃, α-Al₂O₃, MgAl₂O₄ and Mg₂SiO₄. As a result, the corrosion resistance and the adhesion of the MAO coating increase first and then decrease mainly related to the surface morphologies and phase of the coating. The coating has good thermal shock resistance. The performance of micro-arc oxidation coating with MgO micro-powder was improved.

KEYWORDS:

• Micro-arc oxidation
• MgO micro-powder
• 6061 aluminium alloy
• properties

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Ping Wang http://orcid.org/0000-0002-1574-9984