優(yōu)化及膜層特性
(1. 江蘇科技大學(xué) 材料科學(xué)與工程學(xué)院, 鎮(zhèn)江 212003；2. 江蘇科技大學(xué) 機(jī)械工程學(xué)院, 鎮(zhèn)江 212003)
摘 要: 在硅酸鈉、氫氧化鈉、四硼酸鈉和檸檬酸鈉組成的電解液中，采用交流脈沖電源對(duì)ZK60鎂合金進(jìn)行微弧氧化，研究電解液組分對(duì)膜層的影響規(guī)律，并優(yōu)化電解液配方。利用光學(xué)顯微鏡、掃描電鏡(SEM) 、能譜分析(EDS)和X射線衍射分析(XRD)等，研究膜層厚度、表面與截面的微觀組織，通過(guò)靜態(tài)腐蝕質(zhì)量損失法和動(dòng)電位極化曲線法測(cè)試膜層在3.5%NaCl介質(zhì)中的耐蝕性能。結(jié)果表明：各電解液組分濃度對(duì)成膜過(guò)程的電壓變化、膜層厚度和耐蝕性能的影響規(guī)律各不相同，并在不同的合適濃度下獲得厚的膜層和較高的耐蝕性能。通過(guò)單變量實(shí)驗(yàn)和正交實(shí)驗(yàn)優(yōu)化電解液配方：60 g/L NaSiO3+20 g/L NaOH+25 g/L NaB4O7+20 g/L C6H5Na3O7，制備出的膜厚高達(dá)164.89 μm，結(jié)構(gòu)均勻、致密，腐蝕速率極低，僅為ZK60鎂合金空白試樣的1.8%。
關(guān)鍵字: ZK60鎂合金；微弧氧化；Na2SrO3電解液；配方；膜層
（1. School of Materials Science and Engineering,
Jiangsu University of Science and Technology, Zhenjiang 212003, China;
2. School of Mechanical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, China）
Abstract:The micro-arc oxidation process was conducted on ZK60 Mg alloy in an electrolyte composed of NaSiO3, NaOH, NaB4O7 and C6H5Na3O7 by AC pulse electrical source. The coating thickness and microstructural characteristics of coating cross-section and surface were investigated by means of OM, SEM coupled with EDS and XRD. The mass loss and dynamicpotential curves were measured in a 3.5%NaCl solution to evaluate the coating resistance to corrosion. The results reveal that different elements of the electrolyte demonstrate different effects on process voltage, coating thickness and corrosion resistance. For an element of the electrolyte, there is usually a suitable concentration to obtain a thicker coating but which does not guarantee a better corrosion resistance. By means of single variable and orthogonal tests, an optimized electrolyte with a composition of 60 g/L NaSiO3+20 g/L NaOH+25 g/L NaB4O7+20 g/L C6H5Na3O7 was developed. The sample prepared with the optimized electrolyte exhibits good corrosion property with only 1.8% of corrosion rate of blank sample due to its thicker (164.89 μm) and denser coating.
Key words: ZK60 magnesium alloy; micro-arc oxide; NaSiO3 electrolyte; formula; coating
