To overcome the defect of high degradation rate of magnesium (Mg), bioactive coatings with compact structure, sufficient bonding strength and enhanced corrosion resistance are essential for Mg-based biodegradable implants. In this study, a dense Mg-substituted β-tricalcium phosphate and magnesium hydroxide (β-TCMP/Mg(OH)₂) composite coating was prepared on AZ31 alloy via one-step hydrothermal method. The influences of hydrothermal temperature on its composition, microstructure of the surface and interface, bonding strength and corrosion behavior were evaluated. The results showed that the compact composite coating synthesized at 140 °C not only possessed a crack-free bilayered structure with an adequate bonding strength (more than 20.88 ± 1.60 MPa), but also got an extreme high impedance (1197.003 ± 152.817 kΩ cm²) so that significantly enhanced the corrosion resistance and inhibited the formation of pitting corrosion. Furthermore, the in vitro immersion test suggested that the composite coating slower the initial degradation rate of Mg alloys and enhanced its surface bioactivity to some extent.

为了克服镁（Mg）的高降解率的缺陷，具有紧凑结构，足够的结合强度和增强的耐腐蚀性的生物活性涂层对于基于Mg的生物可降解植入物至关重要。在这项研究中，致密的Mg取代的β-磷酸三钙和氢氧化镁（β-TCMP/ Mg（OH）₂通过一步水热法在AZ31合金上制备复合涂层。评估了水热温度对其组成，表面和界面微观结构，结合强度和腐蚀行为的影响。结果表明，在140°C下合成的致密复合涂层不仅具有无裂纹的双层结构，具有足够的粘结强度（大于20.88±1.60 MPa），而且还具有极高的阻抗（1197.003±152.817kΩcm ^2）），从而显着增强了耐蚀性并抑制了点蚀的形成。此外，体外浸渍试验表明，复合涂层减缓了镁合金的初始降解速率，并在一定程度上提高了其表面生物活性。