Effects of Ce(III) on Rate of Formation and Phase Compositions of Ceramic Coatings Formed on Surface of ZAlSi12Cu2Mg1 by Microarc Oxidation

Components of electrolyte has an important effect on the process of microarc oxidation on the surface of aluminum alloys. In this work, ceramic coatings were prepared on ZAlSi12Cu2Mg1 alloy by microarc oxidation through varying content of rare earth Ce(III) from 0 g·L−1 to 0.125 g·L−1 in NaOH-Na2SiO3 electrolyte. The influences of the content of Ce (III) on the rate of formation and phase compositions of ceramic coatings were investigated. The electric vortex thickness indicater was employed to measure the thickness of the ceramic coatings. The phase compositions of ceramic coatings were analyzed by XRD. It was found that the rate of formation firstly increased to some extent and then decreased with the content of Ce(III) increasing. The rate of formation reached the maximum while the content of Ce(III) was 0.025 g·L−1. The maximum rate is c. a. 8.3 μm · min−1. In addition, the phase compositions of ceramic coatings vary with the rate of formation. Ceramic coating was mainly consisted of lots of amorphousness and Al while it formed at the maximum rate. Meanwhile, it was mainly composed of α-Al2O3, γ-Al2O3, Al2SiO5, Al and amorphousness while the coatings formed at the others.