建筑用316L不锈钢表面树脂固化涂层600℃氧化行为分析

为了提高建筑设备表面涂层的防腐能力,通过实验制得一种经纳米改性处理的有机硅固化涂层,并分析其耐高温氧化特性。研究结果表明:当加入35%以上PU时,经过24 h后全部完成了固化过程,将PU和SM配比设定在30%为最优。SM发生固化通过硅羟基脱水缩合来实现,最终获得相互交联的网型组织。从5 min开始直到210 h发生了少量失重,到达210 h时质量表现为相对平稳的状态,涂层可以对基体组织发挥良好保护效果,显著降低氧化速率。氧化前形成致密涂层结构,并未产生裂纹,将涂层升温到600℃氧化处理后形成了更加粗糙的表面组织。涂层和基体之间形成紧密结合,没有发生剥落。随着氧原子不断扩散到涂层中时,不断与铝粉结合转变为氧化铝,抑制了氧气的扩散过程,从而达到了更强的防护效果。

Surface Modification of 316L Stainless Steel with Al/TiO2-Doped Organosilicone Coatings

The surfaces of 316 L stainless steel,a construction material,were modified with the coatings,deposited by spraying of organosilicone resin mixed with Al/TiO₂ nanoparticels and cured in air.The influence of the polyurethane (PU) to polyethyl silicone (SM) ratio on the curing behavior and oxidation resistance at 600℃ was investigated with X-ray diffraction,energy dispersive spectroscopy,scanning electron microscopy and infrared spectroscopy.The results show that the PU/SM ratio has a major impact.Specifically,as the PU/SM increased from 20 wt% to an optimal of 30 wt%,partial solidification of SM resin changed into complete solidification for 24 h and the reticular framework formed because of dehydration and condensation of silicon hydroxyl groups.As the oxidation time increased,the surface-roughness,interfacial-adhesion and oxidation-resistance increased,possibly because the formation of Al₂O_3,originated from a continuous oxidation of Al-powder,prevented O₂-diffusion,enhanced oxidation-resistance and reinforced the interfacial adhesion.