In Situ Formation of ZrO2-Y2O3-Containing Ceramic Coating on Magnesium Alloy by Plasma Electrolytic Oxidation
A ZrO2-Y2O3-containing composite ceramic coating was firstly in situ prepared on AZ91D magnesium alloy by plasma electrolytic oxidation (PEO) technique in an alkaline silicate-containing electrolyte. The morphology, chemical composition and corrosion resistance of the PEO coating were investigated by environmental scanning electron microscopy (ESEM), X-ray diffractometer (XRD), energy dispersive X-ray (EDX) spectrometer, dropping corrosion and electrochemical corrosion test. The results showed that the ceramic coating consisted of two distinct structural layers: an outer loose layer and an inner dense layer; it was composed of t-ZrO2, Y2O3, SiO2 and some magnesium compounds, such as MgO, MgF2 and Mg2SiO4. In addition, the ceramic coating also showed excellent dropping and electrochemical corrosion resistance, which was mainly attributed to its special phase composition and microstructure.
Pengcheng Wang, Liqun Ai, Yungang Li, Xiaoming Sang and Jinglong Bu
H. H. Luo and Q. Z. Cai, "In Situ Formation of ZrO2-Y2O3-Containing Ceramic Coating on Magnesium Alloy by Plasma Electrolytic Oxidation", Advanced Materials Research, Vols. 295-297, pp. 1684-1690, 2011