Feasibility Study of AlN/Al^sub 2^O^sub 3^ Coating on Aluminum Alloy Using Microarc Oxidation Method

This paper attempts to utilize microarc oxidation (MAO) to fabricate the aluminum nitride/aluminum oxide composite ceramic coating on aluminum alloy surface. The effects of MAO voltages, different nitrogen sources, concentration on the surface morphology, and nitrogen content of the coatings are investigated. The results show that the highest nitrogen content (21.22 at%) is obtained on the surface of the coating by the energy dispersive spectrometer analysis under the condition of MAO voltage of 575 V, urea 22.50 g/L, and ammonium hydroxide 20 mL/L condition.