(西安理工大學(xué) 材料科學(xué)與工程學(xué)院，西安 710048)
摘 要: 在硅酸鈉電解液中利用交流脈沖微弧氧化電源對(duì)LY12鋁合金進(jìn)行表面處理，研究微弧氧化初期成膜和后期生長膜層的微觀結(jié)構(gòu)差異，探討鋁合金微弧氧化陶瓷層的形成與生長機(jī)制。結(jié)果表明：初期成膜過程中發(fā)生電化學(xué)沉積反應(yīng)，形成電解液中溶質(zhì)元素的氧化物，增大鋁合金表面的阻抗值；后期生長過程中，基體鋁與OH−放電所產(chǎn)生的活性氧發(fā)生化合反應(yīng)，形成Al2O3陶瓷層，溶質(zhì)元素消耗極少；鋁合金樣品表面獲取的預(yù)制備膜重新參與陶瓷層的生長，可明顯縮短微弧氧化起弧時(shí)間、降低起弧電壓，同時(shí)提升擊穿電壓的穩(wěn)定值。
關(guān)鍵字: 鋁合金；微弧氧化；陶瓷層；生長機(jī)制；預(yù)制備膜
microarc oxidation coating on LY12 aluminium alloy
（School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China）
Abstract:LY12 aluminium alloy was surface treated by microarc oxidation in the Na2SiO3 solution using AC pulse electrical source. The microstructure difference of the coatings formed at different stages of microarc oxidation was researched, and the growth mechanism of ceramic coating on aluminium alloy was discussed. The results show that electrochemical deposition reaction happens during forming incipient coating, and the oxide containing the element of the electrolyte forms. So, this oxide coating increases the impedance value of aluminium alloy. The combination of Al from the substrate and active O generated by the discharge of OH− ion forms Al2O3 coating, and in this process, the element of the electrolyte is consumed little. Since the prefab coating is participated in the process of forming ceramic coating, the prefab coating is prepared on the aluminum alloy surface, it is helpful to shortening arc starting time, reducing the voltage and increasing the steady value of broken down voltage.
Key words: aluminium alloy; microarc oxidation; ceramic coating; growth mechanism; prefab coating
