(1. 重慶理工大學 材料科學與工程學院，重慶 400054； 2. 重慶市特種焊接材料與技術高校工程研究中心，重慶 400054)
摘 要: 為改善鎂合金的耐蝕性和生物相容性，利用化學處理和電化學沉積法在鎂合金AZ31表面制備MgF2/HA復合涂層。采用Hank’s仿生溶液中浸泡和電化學阻抗(EIS)的方法，結合浸泡過程中涂層EIS譜和表面形貌成分的變化，研究MgF2/HA涂層的體外降解行為。結果表明：在Hank’s仿生溶液浸泡過程中，涂層電化學阻抗譜的高頻容抗弧明顯減小，涂層電阻隨浸泡時間而降低。浸泡至5 d時，出現(xiàn)感抗弧，涂層表面區(qū)域產生腐蝕孔核。浸泡至8 d時，鎂合金基體發(fā)生點蝕，點蝕產生的腐蝕產物在孔中堆積形成胞狀突起。浸泡至12 d時，Cl-滲透至鎂合金基體，涂層表面形成MgCl2結晶。浸泡過程中，表面涂層未發(fā)生脫落和明顯的溶解，降解以溶液滲透至基體，然后發(fā)生局部點蝕為主。
關鍵字: 鎂合金；MgF2/HA；涂層；降解性能；生物材料
（1. School of Materials Science and Engineering, Chongqing University of Technology, Chongqing 400054, China; 2. Chongqing Municipal Engineering Research Center of Institutions of Higher Education for Special Welding Materials and Technology, Chongqing 400054, China）
Abstract:In order to improve the corrosion resistance and biocompatibility of magnesium alloys, MgF2/HA composite coatings were prepared on AZ31 magnesium alloy by way of chemical treatment and electrochemical deposition. The evolution of electrochemical impedance spectroscopy (EIS) behavior, as well as the change of the micrograph and chemical composition of the MgF2/HA coating in Hank’s solutions were used to study the degradation process. The results indicate that, during the immersion in Hank’s solutions，the capacitance loop at high frequency decreases obviously, the resistance of the composite coating reduces. The existence of inductance loop of the 5 d-soaked specimen indicates the nucleation of corrosion pits is formed on coated AZ31 alloy. Soak to 8 d, the pitting corrosion occurs, the corrosion products accumulate and form swelling prominence．Soak to 12 d，the Cl- permeates to substrate and MgCl2 crystals form on the coating surface. During the soaking, the surface coating does not fall off and the coating has not obvious dissolved. The degradation happens when the ions in solution permeate to the Mg substrate, and then the localized pitting corrosion occurs.
Key words: magnesium alloy; MgF2/HA; coating; degradation behavior; biomaterials
