提拉法制备二氧化硅陶瓷膜的形貌及性能

Morphology and Properties of Dip-coated Silicon Dioxide Ceramic Films

采用浸渍提拉工艺在复合镀镍的A3钢表面制备氧化硅陶瓷膜。借助扫描电镜观察陶瓷膜的微观形貌,应用电化学阻抗谱测试陶瓷膜的耐蚀性能并揭示耐蚀机理。用平面磨耗试验机测试了陶瓷膜的耐磨性能。结果表明:在500℃下烧结的氧化硅陶瓷膜为类似微裂纹镀铬的表面形貌;在400℃下烧结的氧化硅陶瓷膜与微孔镀铬的表面形貌相似;400℃及500℃烧结后形成无定形的SiO2陶瓷膜。阻抗较高的氧化硅陶瓷膜在3.5%(质量分数)NaCl溶液中的腐蚀过程为扩散控制,能明显抑制镀镍A3钢的腐蚀。氧化硅陶瓷膜降低了复合镀镍层的孔隙率。浸渍提拉成膜后膜层耐磨性能显著优于只复合镀镍的A3钢,浸渍提拉法能提高铁基体复合镀镍的耐磨性能。

A dipping technology was used to prepare thin silica ceramic film on a composite nickel-plat- ed A3 iron substrate. The microstructures of ceramic membrane was observed by SEM. The corrosion resistance properties and the wear-resistance properties were performed by electronical impedance spectroscopy and the flat surface abrasion machine, respectively. The results show that the surface morphology of silicon oxide ceramic coating sintered at 500℃ is similar to micro-crack chromium and the surface morphology of those sintered at 400℃ is similar to micro-porous chrome. Ceramic coatings are amorphous SiO2 after sintered at 400℃ and 500℃. The corrosion process of silica sol gel film with high impedance in 3.5% （mass fraction） NaCl solution is controlled by diffusion procedure, which can obviously inhibit the corrosion of nickel deposit on A3 iron substrate, and that with low impedance is controlled by electrochemical step. The wear-resistance of films after dipcoating is significantly better than that of eletroplating nickel. Silica solgel coating can reduce its porosity. The wear-resistance of composited plating nickel on iron substrate are improved by the silica solgel coatings.