304不锈钢表面纳米铝改性有机硅涂层的高温氧化和电化学行为

研究了纳米铝改性有机硅高温涂层的固化、抗650℃高温氧化性能和耐3.5% NaCl水溶液电化学腐蚀性能。当聚氨酯:有机硅的质量分数达到1:3或更高时，有机硅涂料可以在24 h内完成常温固化。制备出的纳米铝改性有机硅高温涂层表面致密，没有微观裂纹等缺陷。纳米铝改性的有机硅涂层显著提高了304不锈钢抗氧化性能，经1028 h氧化实验，基体几乎没有发生氧化，涂层没有出现开裂和剥落。纳米铝改性的有机硅涂层还显著提高了氧化后的304不锈钢耐氯化钠水溶液腐蚀性能，无涂层的304不锈钢氧化后形成的氧化膜低频阻抗仅3.2 Ω·cm²，而涂装涂层的不锈钢的低频阻抗约为1.1×10⁵ Ω·cm²。

High Temperature Oxidation and Electrochemical Corrosion Behavior of Al Nano-particle Modified Silicone Coating on 304 Stainless Steel

Al nano-particle modified organosilicone coatings were prepared on stainless steel 304SS. The curing properties at room temperatures, high temperature oxidation behavior at 650oC in air and electrochemical corrosion behavior in 3.5% NaCl solution of the coatings were investigated. The silicone coatings can be cured at room temperatures in 24 h only when the mass ratio of polyurethane over silicone is equal to or higher than 1:3. The as-prepared silicone coatings were smooth and free of cracks. The high temperature oxidation resistance of 304SS was greatly improved by applying the modified silicone coating. After oxidized for 1028 h at 650oC in air, the oxide scale on the coated 304SS was hardly discernable, while the coatings remained intact and free of cracks. Besides, after high temperature oxidation, the electrochemical corrosion resistance of the 304SS coated with modified silicone coating in NaCl solution was greatly improved, too. Without the protection of the coating, the impedance at low frequency of oxidized 304SS without coating was as low as 3.2 Ω·cm², while that of the sample with coating was as high as 1.1×10⁵ Ω·cm².