目的 细化Ca–P涂层晶粒，提高其致密性、耐蚀性，得到氨基酸等电点(Isoelectric point，pI)的作用及生物矿化机制。方法 选取谷氨酸、丙氨酸、天冬氨酸，通过60 ℃水浴，在AZ31镁合金表面制备无氨基酸和3种氨基酸Ca–P 涂层，即丙氨酸Ca–P涂层(Ca–PAla)、谷氨酸Ca–P涂层(Ca–PGlu)、天冬氨酸Ca–P涂层(Ca–PAsp)。采用高分辨扫描电子显微镜(SEM)、X射线衍射仪(XRD)和傅里叶红外光谱仪(FTIR)对涂层的微观形貌及成分进行表征分析;通过电化学极化、交流阻抗(EIS)及析氢实验探究涂层在Hank‘s人体模拟体液中的耐蚀性能。结果 Ca–P、Ca–PAla、Ca–PGlu、Ca–PAsp涂层的厚度分别为(8.46±0.43)、(14.39± 0.96)、(8.48±0.16)、(10.07±0.94)μm。涂层的主要组成物相为透钙磷灰石(CaHPO4.2H2O，DCPD)、羟基磷灰石(HA)、缺钙羟基磷灰石(CDHA)。电化学和析氢实验结果表明，氨基酸提高了镁合金Ca–P涂层的耐蚀性。根据自腐蚀电流密度Jcorr的大小，样品可按以下顺序排列，镁合金AZ31 (1.47 × 10^–4 A/cm²) > Ca–P (4.03 × 10^–6 A/cm²) > Ca–PGlu(2.71× 10^–6 A/cm²)> Ca–PASP(8.10× 10^–7 A/cm²)> Ca–PAla(3.70× 10^–7 A/cm²)。结论 在3种氨基酸中，丙氨酸促进成核过程最明显、涂层最厚，且耐蚀性最好。最后，讨论了镁合金表面氨基酸等电点对生物矿化成膜厚度、耐蚀性能的影响机制。

Magnesium and its alloys possess good biocompatibility and mechanical property as absorbable biomedical metals. Their elastic modulus (45 GPa) is very close to that of the bone. However, the disadvantage of the alloys is the rapid degradation rate which can not satisfy the clinical applications. Surface modification is one of the choices for an improvement in the corrosion resistance of magnesium alloys. Chemical conversion is very convenient, effective, and low-cost. According to the reports, small bioorganic molecules such as amino acids can be applied to coat the surface of magnesium alloys with enhanced corrosion resistance and adhesion strength due to molecular recognition, spatial match, and electrostatic adsorption. Amino acids existing in the human body play a critical role in the biomineralization of degradable magnesium-based implants dependent on their molecular structures, type and length of chains, and isoelectric points (pI). Nevertheless, the material-bio-chemical interaction mechanism has not been understood yet.