热喷涂Zn防护涂层及其性能研究

Research on Performance of Thermal Spraying Zn Coating

采用丝材火焰喷涂工艺,分别在Q235钢基体表面设计和制备了热喷涂纯Zn涂层A和经氟碳树脂喷涂封孔处理的复合涂层B,并对这两种涂层分别进行自来水浸泡腐蚀试验。通过磁性测量法、称重法、切格测试法和失重法,分别测定了这两种喷涂涂层的厚度、密度、结合强度和耐蚀性能。借助X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)等检测技术,分别表征了这两种涂层表面的物相组成和显微组织结构。研究结果表明:热喷涂纯Zn涂层A的厚度为281μm,孔隙率约为11.8%,密度约为6.27g·cm^(-3),在自来水中的腐蚀产物主要为Zn_5(CO_3)_2(OH)_6,第一年的腐蚀速度为2.778μm·a^(-1);测定了复合涂层B的厚度为287μm,孔隙率约为7.2%,密度约为6.25 g·cm^(-3),第一年腐蚀速度为1.521μm·a-1。本研究为设计和制备高性能热喷涂Zn防护涂层,并将其应用于钢结构的长效防腐提供必要的理论基础。

To protect steel structures, thermal sprayed Zn coating A and composite coating B, based on the fluorocarbon resin sealing treatment, were designed, prepared and sprayed on the Q235 steel substrated by wire flame coating process, then the fresh water immersion corrosion test was done for these two kinds of coatings. The thickness, density, bonding strength and corrosion resistance property of the coatings were analyzed and measured based on the methods of magnetic measurement, weighing method, cutting grids method and weight-loss method. The microstructures and phases on the surface were characterized by X-ray diffraction（ XRD）, scanning electron microscope（ SEM） and energy dispersive spectrometer（ EDS）,respectively. The results show that the measured thickness, porosity and density of coating A is281 μm, 11.8% and 6.27 g·cm^（-3） respectively, the corrosion products generated in the water was mainly Zn_5（CO_3）_2（OH）_6, and the determined first annual corrosion rate is 2.778 μm·a^（-1）;while the thickness, porosity and density of the coating B is 287 μm, 7.2% and 6.25 g·cm^（-3） respectively, and the first annual corrosion rate is 1.521 μm·a^（-1）.