该研究旨在通过开发锌/羟基磷灰石多层(Zn/HA-ML)涂层来增强镁合金基材的耐腐蚀性和生物活性。通过沉积冷喷涂(CS)Zn底层和高速悬浮火焰喷涂(HVSFS)Zn/HA多层来制备Zn/HA-ML涂层,并将其与CSZn涂层和Zn/HA双层(Zn/HA-DL)涂层进行比较。Phase,微观结构,并检查了粘结强度,分别,通过X射线衍射,扫描电子显微镜,和拉伸粘合测试。使用动电位极化研究了腐蚀行为和生物活性,电化学阻抗谱,和浸没测试。结果表明,HVSFSZn/HA复合层主要由Zn,HA,和ZnO很好地结合到衬底上。Zn/HA-DL涂层中CSZn底层上的HVSFSHA上层由于其热膨胀系数(CTE)不匹配而表现出微裂纹。Zn/HA-ML涂层在不同的层内表现出良好的结合,并且显示出比Zn/HA-DL涂层20.4±2.7MPa更高的结合强度27.3±2.3MPa。CSZn涂层,Zn/HA-DL涂层,和Zn/HA-ML涂层使镁合金基体的腐蚀电流密度分别从3.12±0.75mA/cm2降低到1.41±0.82mA/cm2、1.06±0.31mA/cm2和0.88±0.27mA/cm2,降低了约两倍。Zn/HA-ML涂层在14天的浸泡时间后,腐蚀电流密度降低了六倍,耐腐蚀性提高了两倍,这主要归因于新形成的磷灰石和锌颗粒的腐蚀副产物。Zn/HA-ML涂层有效地结合了CSZn底层的耐腐蚀性和HVSFSZn/HA多层的生物活性,提出了一种低温策略来提高植入物金属的耐腐蚀性和生物活性。
The study aims to enhance the corrosion resistance and bioactivity of Mg alloy substrates through the development of a zinc/hydroxyapatite multi-layer (Zn/HA-ML) coating. The Zn/HA-ML coating was prepared by depositing a cold-sprayed (CS) Zn underlayer and a high-velocity suspension flame sprayed (HVSFS) Zn/HA multi-layer and was compared with the CS Zn coating and the Zn/HA dual-layer (Zn/HA-DL) coating. Phase, microstructure, and bonding strength were examined, respectively, by X-ray diffraction, scanning electron microscopy, and tensile bonding testing. Corrosion behavior and bioactivity were investigated using potentiodynamic polarization, electrochemical impedance spectroscopy, and immersion testing. Results show that the HVSFS Zn/HA composite layers were mainly composed of Zn, HA, and ZnO and were well bonded to the substrate. The HVSFS HA upper layer on the CS Zn underlayer in the Zn/HA-DL coating exhibited microcracks due to their mismatched thermal expansion coefficient (CTE). The Zn/HA-ML coating exhibited good bonding within different layers and showed a higher bonding strength of 27.3 ± 2.3 MPa than the Zn/HA-DL coating of 20.4 ± 2.7 MPa. The CS Zn coating, Zn/HA-DL coating, and Zn/HA-ML coating decreased the corrosion current density of the Mg alloy substrate by around two-fourfold from 3.12 ± 0.75 mA/cm2 to 1.41 ± 0.82mA/cm2, 1.06 ± 0.31 mA/cm2, and 0.88 ± 0.27 mA/cm2, respectively. The Zn/HA-ML coating showed a sixfold decrease in the corrosion current density and more improvements in the corrosion resistance by twofold after an immersion time of 14 days, which was mainly attributed to newly formed apatite and corrosion by-products of Zn particles. The Zn/HA-ML coating effectively combined the advantages of the corrosion resistance of CS Zn underlayer and the bioactivity of HVSFS Zn/HA multi-layers, which proposed a low-temperature strategy for improving corrosion resistance and bioactivity for implant metals.