新型PEO/纳米结构ZrO2镁合金涂层的抗菌活性及腐蚀行为

摘要

为了增强镁合金的耐腐蚀性和抗菌活性,先采用等离子体电解氧化(PEO)在镁合金上制备一层结合层,再用空气等离子喷涂(APS)制备纳米结构ZrO2表面涂层.采用电化学试验研究涂层样品的腐蚀行为,采用琼脂扩散法对其进行大肠杆菌病原菌抑菌活性评价,并与无涂层样品进行对比.与PEO涂层和无涂层镁合金相比,PEO/纳米ZrO2涂层样品的腐蚀电流密度最低,电荷传递阻力最高,相位角和阻抗模量最高.PEO结合涂层被纳米ZrO2表面涂层完全密封,能够显著延缓侵蚀性离子向镁合金表面迁移,显著提高镁合金在模拟体液(SBF)中的耐蚀性.此外,PEO/纳米ZrO2涂层的抗菌活性也高于PEO涂层和无涂层镁合金,这是由于ZrO2纳米颗粒通过作用于细胞膜而降低了大肠杆菌的生长速率.%Plasma electrolytic oxidation (PEO) was developed as a bond coat for air plasma sprayed (APS) nanostructure ZrO2 as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method toward Escherichia coli (E. coli) bacterial pathogens, respectively. The lowest corrosion current density and the highest charge transfer resistance, phase angle and impedance modulus were observed for PEO/nano-ZrO2 coated sample compared with those of PEO coated and bare Mg alloys. Nano-ZrO2 top coat which has completely sealed PEO bond coat is able to considerably delay aggressive ions transportation towards Mg alloy surface and significantly enhances corrosion resistance of Mg alloy in simulated body fluid (SBF) solution. Moreover, higher antibacterial activity was also observed in PEO/nano-ZrO2 coating against bacterial strains than that of the PEO coated and bare Mg alloys. This observation was attributed to the presence of ZrO2 nanoparticles which decelerate E. coli growth as a result of E. coli membranes.