水性硅酸盐富锌涂层的SEM/EDS研究

A SEM/EDS Study on the Waterborne Silicate Zinc-Rich Coatings

利用自制的不同模数(SiO2/K2O摩尔比)硅酸钾溶液与锌粉复配制备成系列模数硅酸盐富锌涂料.采用场发射电子显微镜(SEM)研究了碳钢上水性硅酸钾富锌涂层在质量分数为3.5%NaCl溶液中腐蚀形貌的变化,分析了水性硅酸钾溶液的模数对涂层结构及其防腐蚀性能的影响.采用能谱仪(EDS)测定了涂层在浸泡前及不同浸泡时期表面组成的变化,并据此分析了腐蚀产物对涂层结构和涂层防腐蚀性能的影响.结合腐蚀产物的X-ray衍射图谱(XRD)分析了腐蚀产物的组成.研究结果表明:水性硅酸钾溶液模数的增加有利于提高Zn粉颗粒间的粘接形成致密的富锌涂层.使用过程中该涂层的腐蚀产物能够增强涂层对腐蚀介质渗透的屏蔽效应,并与涂层中Zn粉对基材的阴极保护产生协同作用.

A series of potassium silicate solution with different SiO2/K2O mole ratio was prepared and mixed with Zn dust to form serial Zn-rich coatings. Scanning electron microscope （SEM） was used to observe the morphological change of the gn-rich coatings on mild steel immersed in 3.5 % NaCl solution. The influence of the SiO2/K2O molar ratio of potassium silicate on coating surface configuration and anti-corrosion performance was discussed. Besides, energy diffraction spectroscopy （EDS） and X-ray diffraction （XRD） were employed to determine the compositions of the coating surface before immersion and the corrosion product at different immersion stages. It was found that the increment of SiO2/K2O ratio reinforced the binding among Zn dust to form a dense coating, and the corrosion products could enhance the shield effect of the coatings and exhibited a synergic effect on its anti-corrosion performance with Zn dust.