钢结构用锌-铝合金涂层的耐蚀性研究

Study on corrosion resistance of zinc-aluminum alloy coating for steel structure

涂层作为物理屏障,可阻断钢结构与水、氧气、盐等的接触,起到防腐作用,可大幅延长建筑钢的使用寿命,减少维护和修复费用,保障结构安全可靠。因此,为研究建筑钢结构用锌-铝合金涂层的耐蚀性,用铝粉与锌粉为主要材料,混合辅料,制备涂层浆液,用浸涂工艺在建筑钢结构上涂覆锌-铝合金浆料。以氯化钠溶液为腐蚀介质,测试铝粉质量分数分别为15%、25%、35%、45%时,该涂层的腐蚀微观、宏观形貌及质量损失;测试不同浓度氯化钠溶液与温度下涂层的耐蚀性。结果表明:铝粉质量分数为45%时制备的锌-铝合金涂层,微观形貌更致密,宏观腐蚀形貌未出现明显黄锈,且该铝粉用量下涂层腐蚀后质量损失最小。氯化钠溶液质量分数为10%且温度较高时,锌-铝合金涂层的耐蚀性最好。

As a physical barrier,the coating can block the contact between the steel structure and water,oxygen,salt,etc.,play an anti-corrosion role,can greatly extend the service life of the construction steel,reduce maintenance and repair costs,and ensure the safety and reliability of the structure.Therefore,in order to study the corrosion resistance of zinc-aluminum alloy coating for building steel structure,the coating slurry was prepared with aluminum powder and zinc powder as the main materials and mixed auxiliary materials,and the zinc-aluminum alloy slurry was coated on the building steel structure by dipping coating process.When the mass fraction of aluminum powder is 15%,25%,35%and 45%,the corrosion microstructure and quality loss of the coating were measured with NaCl solution as the corrosion medium.The corrosion resistance of the coating was tested at different concentrations of NaCl solution and temperature.The results show that the zinc-aluminum alloy coating with 45%aluminum powder has denser micro-morphology,no obvious yellow rust on macro-corrosion morphology,and the quality loss of the coating after corrosion is minimal with the amount of aluminum powder.When the mass fraction of NaCl solution is 10%and the temperature is high,the corrosion resistance of zinc-aluminum alloy coating is the best.