Effects of additives in electrolyte on characteristics of ceramic coatings formed by microarc oxidation

Abstract

The effects of adding Na2 WO4. 2H2O and SiC powder to the electrolyte on the characteristics of ceramic coatings on Al based alloys formed by microarc oxidation were studied. The ceramic coating quality was improved by the two additives, but the addition of Na2 WO4. 2H2O was more effective, as it improved the formation of Al2O3 phase in the ceramic coating, increased the ratio of the internal dense region to the whole ceramic coating, optimised the ceramic coating phase structure, and improved its wear resistance. The SiC powder was able to enter into the ceramic coating and improve its wear resistance, at the same time increasing the friction coefficient of the coating.

Formation of ceramic alumina nanocomposite coatings on aluminium for enhanced corrosion resistance

“…(Wei et al, 2004;Curran and Clyne, 2005a,b;Wang et al, 1999). It was reported Ma et al, 2006) that higher current density and lower solution temperature benefit film growth.…”

Kinetics and Properties of Micro Arc Oxidation Coatings Deposited on Commercial Al Alloys

“…[9,10,11] The research related to development of the MAO process has intensified in the last 5 years. Voevodin and co-workers in the United States, [12] Matthews and co-workers in the United Kingdom, [13] Wang and co-workers in China, [14] Sundararajan et al in India, [15,16] and Mecuson et al in France [17] have contributed to the further development of the MAO technique in conjunction with improving our understanding of the mechanism of coating formation and coating properties. The overall wear resistance offered by the MAO coatings under the abrasion, erosion, and sliding wear modes was found to be comparable to that of the bulk alumina and better than the thermal-sprayed alumina and hard anodized coatings.…”

Effects of fluoride on the structure and properties of microarc oxidation coating on aluminium alloy

“…Wang et al [20] and Zheng et al [21] have found that Na 2 WO 4 could improve the formation of Al 2 O 3 phase in the ceramic coating and improve its wear resistance. Butyagin et al [22] reveal that introducing compounds of transition metals into the solution can lead to the changes in the coatings' structure, and the coatings obtained are capable of enduring higher thermocyclic loads.…”