氟处理的镁合金表面电化学沉积Ca-P涂层的研究

Calcium Phosphate Coatings Prepared by Electrochemical Deposition on Fluoride-treated Magnesium Alloy

为改善镁合金的耐蚀性和生物相容性,以氟处理的AZ31镁合金为基体,通过Ca(OH)2处理后使其表面改性,用电化学沉积法在其表面制备了Ca-P涂层。通过SEM、EDS、XRD和FTIR分析了涂层的形貌、化学成分和相组成。结果表明:经HF酸处理后,镁合金表面形成具有微孔的氟转化层,氟转化层在Ca(OH)_2溶液浸泡后形成具有微纳米孔隙的CaF_2层;相比于未经Ca(OH)_2处理的氟转化膜表面,具有微纳米孔隙的富钙层更有利于诱导含磷基团和钙离子的形核,电化学沉积所得的Ca-P涂层更致密均匀,晶体结晶更完整;电化学沉积后的涂层由长约70μm、宽约30μm的片状透钙磷石(DCPD,CaHPO_4·2H_2O)晶体组成,碱热处理后涂层表面形成大量绒毛状物质,DCPD转变为HA,HA涂层也是由呈花簇状生长的片状晶体构成。

To improve the corrosion resistance and biocompatibility of magnesium alloys,Ca-P coatings were fabricated on the fluoride-treated AZ31 magnesium alloy by electrochemical deposition.Before the electrochemical deposition,the fluoride-treated AZ31 alloy was immersed in Ca（OH）_2 solution to modify the surface of the fluoride conversion film.The morphology of the coating was investigated by SEM,the composition by EDS and the structure by XRD as well as FTIR.The results show that an MgF_2 conversion film with micro-pores is formed on AZ31 alloy through the fluoride treatment.After soaking in Ca（OH）_2,a CaF_2 film with micro/nano pores is formed on the fluoride-treated surface,which is advantageous to the nucleation of calcium phosphate.The Ca-P coating deposited on Ca（OH）_2-immersed sample is more uniform and compact than the untreated one.The coating is composed of flake-like crystals of brushite（DCPD,CaHPO_4·2H_2O） with about 70μm in length and 30 μm in width and converted to hydroxyapatite（HA） coating which is covered by villous deposition after alkaline-heat treatment.