Corrosion Resistance of Ceramic Coatings Prepared by Spraying Micro-arc Oxidation on Aluminum Alloy Weld Zone

QIU Ji, SHUAI Gang, CAI Jia-hui

Surface Technology ›› 2015, Vol. 44 ›› Issue (12) : 116-121.

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Surface Technology ›› 2015, Vol. 44 ›› Issue (12) : 116-121. DOI: 10.16490/j.cnki.issn.1001-3660.2015.12.019
Surface Failure and Protection

Corrosion Resistance of Ceramic Coatings Prepared by Spraying Micro-arc Oxidation on Aluminum Alloy Weld Zone

  • QIU Ji, SHUAI Gang, CAI Jia-hui
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Abstract

Objective To study the feasibility of using spraying micro-arc oxidation to improve the anti-corrosion property of aluminum alloy weld zone. Methods A ceramic coating was prepared on the aluminum alloy weld zone using a self-developed spraying micro-arc oxidation equipment, and compared with a ceramic coating prepared by immerging micro-arc oxidation using the same parameters. The surface and cross-section microstructure of the ceramic coating were observed by SEM, and the elemental composition of ceramic coating cross-section was analyzed. CASS corrosion test and potentiodynamic polarization curve experiment were used respectively to test the anti-corrosion performance of the coating, and analyze the corrosion resistance of the coating. Results The ceramic coatings prepared with the two different methods showed similar microstructure, there were many "craters" on the surface, accompanied by cracks. The cross-section was loose and porous. The major elements were Al and O. All three types of samples were corroded to varying degrees after 240 h salt spray corrosion. The aluminum alloy weld substrate was most severely corroded, followed by immerging and spraying samples, with corrosion weight loss ratios of 0. 0072,0. 0039,0. 0023 g / cm2 , respectively. The results of polarization curves showed that the corrosion potentials of aluminum alloy substrate, weld substrate, immerging ceramic coating and spraying ceramic coating were -0. 794, -0. 742, -0. 615 and -0. 578 V, respectively. Conclusion The corrosion resistance performance of ceramic coating prepared by spraying micro-arc oxidation was relatively good, reaching the preparation requirements. The spraying method could be used in conditions that the immerging method was not suitable.

Key words

aluminum alloy; weld zone; micro-arc oxidation; spraying; microstructure; corrosion resistance

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QIU Ji, SHUAI Gang, CAI Jia-hui. Corrosion Resistance of Ceramic Coatings Prepared by Spraying Micro-arc Oxidation on Aluminum Alloy Weld Zone[J]. Surface Technology. 2015, 44(12): 116-121

Funding

Supported by the Equipment Pre-research Program(51327040101)
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