性能的影響
(1. 蘭州理工大學 甘肅省有色金屬新材料省部共建國家重點實驗室，蘭州 730050；
2. 甘肅聯(lián)合大學 化工學院，蘭州 730000)
摘 要: 采用恒定小電流密度工藝于硅酸鹽體系中在AZ91D鎂合金表面制備微弧氧化膜。采用數(shù)字式涂層測厚儀、掃描電子鏡、表面粗糙度測量儀和涂層附著力劃痕試驗機等研究其微觀結構，利用電化學工作站和球－塊往復式摩擦試驗機進行耐蝕性和耐磨性的評定。結果表明：隨著氧化時間的延長，陽極電壓趨于穩(wěn)定；氧化膜層的厚度和粗糙隨之增大；氧化膜層的結合力、孔隙率則先增大后減小，都在60 min時出現(xiàn)最大值；膜層表面熔融物顆粒尺寸增大，大孔洞的數(shù)目隨之增多，且分布變得不均勻；氧化時間為40 min時制備的膜層耐蝕能力最強并具有良好的耐磨性。
關鍵字: AZ91D鎂合金；微弧氧化；恒定小電流密度；耐蝕性；耐磨性
micro-arc oxidation coatings of AZ91D magnesium alloy
（1. State Key Laboratory of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology,
Lanzhou 730050, China;
2. College of Chemical and Industry, Gansu Lianhe University, Lanzhou 730000, China）
Abstract:Micro-arc oxidation (MAO) coatings were formed on AZ91D alloy surface by invariable small current density process in silicate electrolyte. The microstructures were studied by digital coating thickness gauge, SEM, surface roughness measuring instrument and coating adhesion scratch test machine, and the corrosion and wear resistance were assessed by electrochemistry workstation and ball-block reciprocating friction tester. The results indicate that with the increase of the oxidation time, the anode voltages are stabilized, the thickness and roughness are always increased. The porosity and bonding force of the MAO coating first increase, and then decrease, they are all reach their maximum values at 60 min. The melting particles of surface are bigger and the number of large holes is increased, and the distribution becomes uneven. The coating has good corrosion resistance and the best wear resistance when the oxidation time is 40 min.
Key words: magnesium alloy AZ91D; micro-arc oxidation; invariable small current density; corrosion resistance; wear resistance
