pH值对镁合金表面水热沉积磷酸钙涂层微观形貌和腐蚀性能的影响（英文）

Microstructure and Corrosion Properties of Calcium Phosphate Coating on Magnesium Alloy Prepared by Hydrothermal Treatment at Various pH Values

为改善镁合金的耐蚀性和生物相容性,采用水热法在不同p H值条件下于AZ31镁合金表面制备了磷酸钙(Ca-P)涂层。利用XRD、SEM和EDS分析了不同pH值下涂层的物相组成、微观形貌和化学成分;在Hank’s仿生溶液中采用电化学测试和浸泡的方法研究了涂层的生物腐蚀行为。结果表明:水热处理的pH值影响涂层的相组成和微观形貌,涂层的微观形貌影响涂层的防护性能。当pH值为6时,Ca-P涂层由OCP(Ca_8H_2(PO_4)_6·5H_2O)组成,当p H值增加到8和10时,Ca-P涂层为羟基磷灰石(HA)。p H值为8时,HA涂层呈蜂窝状;pH值为10时,HA涂层由纳米尺度的棒状晶体构成,该涂层在Hank’s溶液中能有效阻止溶液的渗透而保护基体。

Calcium phosphate（Ca-P）coatings were deposited on AZ31 magnesium by hydrothermal treatment at various pH values to improve the corrosion resistance and biocompatibility of magnesium alloys.The crystal phase,morphology and composition of the coatings were investigated by XRD,SEM and EDS,respectively.Electrochemical measurements and immersion tests were performed in Hank’s solution to examine the bio-corrosion behaviors of the coated specimens.The results show that the pH value of solutions influences the phase composition and microstructure of the coating.And the degree of protection provided by the Ca-P coating varies with its microstructure.The deposited Ca-P coating treated at pH=6 is composed of OCP（Ca8H2（PO4）6·5H2O）.When the pH value increases to 8 and 10,only the HA is formed.The HA coating with nano-scale and rod-like crystals prepared at pH=10 can prevent the penetration of solution more effectively than the OCP coating at pH=6 and the honeycomb-like HA coating at pH=8.