کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5366274 | 1388346 | 2009 | 8 صفحه PDF | دانلود رایگان |

This study focuses on mechanism of ceramic coating on Al-Si alloys with bulk primary Si using plasma electrolytic oxidation (PEO) technology. Al-Si alloys with 27-32%Si in weight were used as substrates. The morphologies, composition and microstructure of PEO coatings were investigated by scanning electron microscopy (SEM) with energy dispersive X-ray system (EDX). Results showed that the PEO process had four different stages. The effect of bulk Si is greatly on the morphology and composition of coatings at first three stages. Anodic oxide films formed on Al and Si phases, respectively. When the voltage exceeded 40Â V, glow appeared and concentrated on the localized zone of interface of Al and Si phase. Al-Si-O compounds formed and covered on the dendrite Si phase surface, and the coating on bulk Si, which was silicon oxide, was rougher than that on other phase. If the treatment time was long enough, the coatings with uniform surface morphologies and elements distribution will be obtained but the microstructure of inner layer is looser due to the bulk Si.
Journal: Applied Surface Science - Volume 255, Issue 23, 15 September 2009, Pages 9531-9538