纳米SiO_2对低碳钢表面磷化膜的结构和耐蚀性的影响

Influence of Nano SiO_2 on Structure and Corrosion Resistance of Phosphate Coating on Surface of Mild Steel

使用加入纳米SiO_2的低温磷化液在低碳钢表面制备了磷化膜,并对其形貌、成分、厚度、粗糙度以及耐蚀性进行表征,研究了纳米SiO_2对磷化膜结构和性能的影响。结果表明,纳米SiO_2不是磷化膜的主要成分,但是在磷化液中添加纳米SiO_2使磷化膜增厚、细化磷化膜晶粒、提高磷化膜致密度,并提高了磷化膜的耐腐蚀性能。当纳米SiO_2的加入量为2g/L时,磷化膜在5%NaCl溶液中的耐腐蚀性最好,府蚀电流密度为0.231μA/cm^2。

Under the low temperature conditions,phosphate coating on the surface of mild steel by the addition of nano-SiO_2 in phosphating solution was prepared in this paper.The influence of nano-SiO_2 on structure and performance of phosphate coating was investigated by SEM,XRD,EDS,thickness, surface roughness and corrosion electrochemical testing.The results show that although nano-SiO_2is not main component of phosphate coating,but the coating thickness decreases with increasing the concentration of nano-SiO_2,nano-SiO_2 can reduce the crystal size of coating and increase the density and corrosion resistance of coating.When the nano-SiO_2 concentration is 2 g/L,the best corrosion resistance of phosphate coating is obtained in 3.5%NaCI solution.The corrosion current of phosphating sample was 0.231μA/cm^2 in 5%NaCI solution.