磷酸鹽轉(zhuǎn)化膜耐蝕性的影響
(1. 山東科技大學(xué) 材料科學(xué)與工程學(xué)院，青島 266510；
2. 重慶理工大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400050)
摘 要: 采用化學(xué)沉積方法在AZ31鎂合金表面制備鋅鈣系磷酸鹽轉(zhuǎn)化膜。利用掃描電子顯微鏡(SEM)和電化學(xué)方法研究鍍液溫度對(duì)鎂合金AZ31表面磷酸鹽轉(zhuǎn)化膜表面形貌及其耐蝕性能的影響。利用電子能譜儀(EDS)、光電子能譜(XPS)和X射線衍射儀(XRD)分析膜層化學(xué)成分、相結(jié)構(gòu)。研究表明：當(dāng)溫度為50 ℃時(shí)，轉(zhuǎn)化膜層晶粒均勻、完整，耐蝕性較好；膜層化學(xué)成分主要由O、P、Zn和Mg元素以及微量Ca組成，主要相組成為Zn3(PO4)2·4H2O；鋅鈣磷酸鹽轉(zhuǎn)化膜比磷酸鋅轉(zhuǎn)化膜具有更小的晶粒和更好的耐蝕性。
關(guān)鍵字: 鎂合金；磷酸鹽轉(zhuǎn)化膜；鍍液溫度；耐蝕性
（1. School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266510, China;
2. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400050, China）
Abstract:Zinc calcium phosphate conversion films were prepared via chemical deposition on AZ31 magnesium alloy. The influence of the temperature of phosphate baths on the surface morphologies of phosphate conversion films on AZ31 magnesium alloy and their corrosion resistance were investigated by scanning electron microscopy (SEM) and potentiodynamic electrochemical tests, respectively. And the phase constitutes and chemical compositions of the coatings were analyzed by electron energy X-ray spectrum (EDS), X-ray photoelectron spectrum (XPS) and X-ray diffraometry (XRD). The results show that the chemical conversion coatings, which are mainly composed of Zn3(PO4)2·4H2O, contain O, P, Zn and Mg as well as a trace of Ca. The phosphate conversion films are characterized to be homogenous fine grains and completely covered on the surface; and the corrosion resistance of the coatings obtained at the temperature of 50 ℃ is optimum. The calcium-containing phosphate conversion films with finer grains on magnesium alloy can more significantly enhance the corrosion resistance than zinc phosphate conversion films.
Key words: magnesium alloy; phosphate conversion film; bath temperature; corrosion resistance
