(蘭州理工大學(xué) 省部共建有色金屬先進(jìn)加工與再利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 在硅酸鹽體系中對(duì)AZ91D鎂合金進(jìn)行微弧氧化處理，探討膜層致密性的研究方法，推導(dǎo)膜層密度的計(jì)算公式，定量分析膜層表面微孔的大小、分布及表面孔隙率隨時(shí)間的變化，研究上述因素對(duì)膜層耐蝕性的影響。結(jié)果表明：成膜物質(zhì)基本不隨時(shí)間的變化而發(fā)生改變，使膜層的致密性可以通過(guò)密度來(lái)間接研究；隨著時(shí)間的延長(zhǎng)，膜層表面微孔逐漸變大，各微孔之間的大小差異及形狀差異不斷增大，膜層的表面孔隙率從8%逐漸增大到15%。處理時(shí)間為5和10 min時(shí)，膜層較致密，20 min后，膜層的致密度明顯減小，時(shí)間繼續(xù)延長(zhǎng)，致密度基本保持不變。受膜層較大厚度、較高致密度、較少表面缺陷等多種優(yōu)勢(shì)共同存在的影響，30 min時(shí)，試樣的耐蝕性最好。
關(guān)鍵字: 鎂合金；微弧氧化；孔隙；致密性；耐蝕性
（State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The coatings on AZ91D magnesium alloys were prepared by micro-arc oxidation (MAO) in silicate-containing electrolyte. The method to research the compactness of the coatings was discussed and a calculation formula of the density of the coatings was deduced. Meanwhile, the size and amount of the micro pores on the surface and the surface porosity of the coatings treated for different times were analyzed quantitatively. And the effect of the above factors on the corrosion resistance of the coatings was researched. The results show that, the phase composition of the coatings has no change with the extension of treatment time, so, the compactness of the coatings can be researched indirectly through the density of the coatings. With prolonging treatment time, the micro pores on the surface of the coatings become bigger constantly. The differences in size and shape of the micro pores also become more serious. The surface porosities of the coatings gradually increase from 8% to 15%. After treating for 5 and 10 min, the compactness of the coatings is large, however, after treating for 20 min, the compactness decreases greatly and basically remains unchanged. The corrosion resistance of the sample treated for 30 min is the best, because the coatings has a larger thickness, higher compactness and less surface defects on the surface.
Key words: magnesium alloy; micro-arc oxidation; micro-pore; compactness; corrosion resistance
