Microarc oxidation coatings containing TiC and NbC on magnesium alloy

ABSTRACT

Microarc oxidation (MAO) coatings were formed on AZ91D magnesium alloy in zirconate–phosphate electrolytes with and without the addition of titanium carbide (TiC) and niobium carbide (NbC) particles. Surface morphologies, structures, compositions and corrosion resistance of the MAO coatings were investigated. The MAO coating formed in the based electrolyte was mainly composed of MgO, Mg₂Zr₅O₁₂ and some amorphous phases. TiC and NbC particles in the electrolyte were incorporated and uniformly distributed in the MAO coatings. Both particles increased the thickness and compactness of the MAO coatings. Electrochemical measurements results indicated that the TiC and NbC particles in the electrolyte improved the corrosion resistance of the MAO coating, and those formed in the electrolyte with NbC particles showed the best corrosion resistance.

KEYWORDS:

• Magnesium alloy
• Microarc oxidation
• titanium carbide
• niobium carbide
• corrosion resistance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51301070], Engineering Technology Research Center of Henan Province [grant number [2016]221-35], Key Program of Henan Provincial Department of Education [grant number 18A430018], and College students innovation and entrepreneurship training program of North China University of Water Conservancy and Electric Power [grant number 2018XB002].