(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: 在硅酸鹽體系電解液中對(duì)AZ91D鎂合金進(jìn)行微弧氧化處理，使用電子外徑千分尺、渦流測(cè)厚儀、掃描電子顯微鏡(SEM)以及電子探針顯微分析儀(EPMA)對(duì)試樣尺寸、膜層厚度、微觀形貌及所含元素的分布進(jìn)行檢測(cè)，采用分界區(qū)直接觀察法、全基體直接測(cè)量法和膜層宏觀測(cè)量計(jì)算法3種方法研究膜層的生長(zhǎng)方式。結(jié)果表明：第一種方法從膜層截面中直接觀察到鎂合金微弧氧化膜的確存在向內(nèi)、向外生長(zhǎng)的現(xiàn)象，為膜層的生長(zhǎng)方式提供了直觀的證據(jù)；第二種方法直接、直觀地對(duì)基體和膜層的尺寸變化同時(shí)進(jìn)行觀察與測(cè)量，同樣揭示存在膜層同時(shí)向內(nèi)、向外生長(zhǎng)的現(xiàn)象，且膜層向外的生長(zhǎng)速率大于向內(nèi)的；第3種方法的結(jié)果再次表明膜層存在向內(nèi)、向外生長(zhǎng)的現(xiàn)象，并且不同時(shí)間下膜層向外生長(zhǎng)的尺寸均大于向內(nèi)的尺寸，但膜層整體的生長(zhǎng)速率逐步降低。
關(guān)鍵字: 鎂合金；微弧氧化；硅酸鹽電解液；生長(zhǎng)方式
（State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals,
Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:AZ91D magnesium alloys were treated by micro arc oxidation (MAO) in silicate-containing electrolyte. The sample dimension, thickness, morphology and element distribution of the coatings were examined by micrometer with electronic digital display, thickness tester, scanning electron microscope (SEM) and electron-probe micro analyzer (EPMA), respectively. The coating growth was investigated by three methods, containing directly observing the boundary area, macroscopically calculating the coating and directly measuring the whole substrate. The results show a phenomenon that the coatings growing inward and outward is observed intuitively in cross-section morphology of the MAO coating on magnesium alloys through the first method, and it proves the most intuitive evidence to illustrate how the coating grows. By the second method, dimensional changes of the substrates and the coatings can be observed and measured visually and the results also show that the coatings grow inward and outward at the same time, with lager grow rate outward compared with that of inward. The results of the third method once again show the coatings grow inward and outward simultaneously and the dimensions growing outward is lager than that of inward under different times, but the growth rate of the whole coating gradually reduces.
Key words: magnesium alloy; micro arc oxidation; silicate-containing electrolyte; growth rule
