低温制备不锈钢表面含铜磷酸铝涂层及抗菌性能研究

利用磷酸二氢铝的固化反应在316不锈钢表面制备了不同含量Cu²⁺的磷酸铝涂层(Cu: Al=0.025、0.05、0.1)。差示扫描量热分析及X射线衍射表明涂层材料可在≤250℃下固化, 主要固化产物为AlH₂P₃O₁₀?2H₂O、AlPO₄和Al₈H₁₂(P₂O₇)₉。Cu²⁺加入后产生了含铜的新相Cu₂P₂O₇。与大肠杆菌共培养12 h后各含Cu²⁺涂层表现出抗菌性, 且抗菌能力与Cu²⁺含量正相关; 接触24 h后, 所有含Cu²⁺涂层表面均无活菌检出。菌悬液中加入EDTA有效抑制了涂层抗菌活性, 表明涂层抗菌性能来自表面溶出的Cu²⁺。拉伸试验表明涂层结合强度在14.5~18.1 MPa范围。与无涂层的不锈钢相比, 涂覆涂层后样品的腐蚀电流密度下降了2个数量级。

Low-temperature Preparation of Cu-containing Aluminum Phosphate Coatings on Stainless Steel and Antibacterial Properties

Aluminum phosphate coatings containing different levels of Cu²⁺ ions (Cu/Al molar ratio: 0.025, 0.05, 0.1) were prepared on 316-stainless steel based on the curing reaction of monoaluminium phosphate (MAP). The curing behaviors of the starting materials and phase compositions of the cured products were studied by differential scanning calorimetry and X-ray diffraction, respectively. Results indicate that the copper-free MAP cures at ≤250℃ to form 3 major phases: AlH₂P₃O₁₀·2H₂O, AlPO₄, and Al₈H₁₂(P₂O₇)₉. When Cu²⁺ ions are introduced into the MAP, an additional phase of Cu₂P₂O₇ appears in the cured product. E. coli was inoculated on the surfaces of coatings to evaluate their antibacterial properties. After co-culture with E. Coli for 12 h, all Cu²⁺-containing coatings exhibit antibacterial effect and show a positive association between Cu²⁺ content and antibacterial activity. After co-culture for 24 h, no viable bacteria remain on any Cu²⁺-containing coating. The addition of ethylenediaminetetraacetic acid to the culture medium substantially inhibits the antibacterial activities of all coatings, confirming that the antibacterial effect is attributed to the release of Cu²⁺ ions from coatings. Pull-out tests show that the bonding strengths of the coatings range between 14.5-18.1 MPa. Potentiodyanmic polarization indicates that the coatings reduce the corrosion current density of the stainless steel substrate by approximately two orders of magnitude.