溶胶—凝胶法制备等离子喷涂涂层封孔层的研究

发布时间：2018-01-18 05:11

  本文关键词：溶胶—凝胶法制备等离子喷涂涂层封孔层的研究　出处：《武汉理工大学》2010年硕士论文　论文类型：学位论文

  更多相关文章： 溶胶-凝胶法 封孔剂 耐腐蚀性能 耐高温氧化性 防污性

【摘要】： 等离子喷涂技术具有涂层形成速度快、可喷涂材料广、涂层性能良好、适用范围广、成本低等优点而在材料表面工程方面获得了广泛的应用。但由于其自身固有的性质,使其涂层不可避免的具有孔隙的存在,孔隙的存在会使涂层的耐腐蚀性能下降,因此为了提高涂层的耐腐蚀性能必须对涂层进行封孔处理。封孔处理的方法很多,其中采用封孔剂进行封孔处理应用较为广泛。通常采用微晶石蜡、乙烯树脂等有机封孔剂进行封孔,但由于其耐热性差、具有挥发性和可燃性、对环保不利等缺点,应用范围受到了限制,所以近年来无机封孔剂的研究正在不断发展。 本文采用溶胶-凝胶法研制了一种新型的Si02-Al203溶胶封孔剂,用浸渍-提拉法对等离子喷涂涂层进行了封孔处理。应用XRD、FTIR、TG-DTA和SEM等测试手段对封孔层的结构、热稳定性和形貌等进行了表征,采用全浸泡腐蚀试验、耐高温氧化试验及接触角测试等对涂层的耐腐蚀性能、耐高温性能及防污性能进行了分析研究。 经测试得,研制的新型SiO2-Al203无机非晶态溶胶封孔剂具有良好的热稳定性。封孔处理前后的SEM照片及孔隙率测试表明,封孔后涂层的孔隙率得到了明显的降低,并且涂层的致密性得到了显著提高；涂层断面的SEM及元素面分布分析显示,所制备的Si02-Al203封孔剂具有极好的浸渗性和封孔能力。封孔前后的耐腐蚀对比实验表明,封孔后涂层的耐酸、碱和盐腐蚀的性能均提高了50%以上,从而增强了涂层对基体的保护作用。耐高温氧化测试结果表明,经封孔处理后试样在500℃下的耐高温氧化性能得到了较大提高。 接触角测试结果表明,无机封孔剂封孔处理后涂层对水的接触角为83.8°,无机-有机复合封孔后涂层对水的接触角为101°,故经复合封孔处理后的涂层能够起到较好的防污作用。腐蚀试验结果表明,无机-有机复合封孔处理后试样的耐腐蚀性能比无机封孔试样又提高了27%以上,说明复合封孔层不仅可以降低涂层的表面能,起到防污作用,而且可以对无机封孔剂未完全封好的孔隙起到进一步的封孔作用。
[Abstract]:Plasma spraying technology has the advantages of fast coating forming speed, wide spraying material, good coating performance and wide application range. Because of its low cost and other advantages, it has been widely used in material surface engineering. However, due to its inherent properties, the coating inevitably has pores. In order to improve the corrosion resistance of coatings, it is necessary to seal the pores of the coatings. There are many ways to seal the coatings. The microcrystalline wax, ethylene resin and other organic sealing agents are usually used to seal the pores, but they are volatile and flammable because of their poor heat resistance. Due to the disadvantage of environmental protection, the application scope is limited, so the research of inorganic sealing agent is developing continuously in recent years. A new Si02-Al203 sol sealing agent was developed by sol-gel method. The plasma sprayed coating was treated by impregnation and Czochralski method. The structure, thermal stability and morphology of the sealing layer were characterized by TG-DTA and SEM. The corrosion resistance, high temperature resistance and antifouling performance of the coatings were studied by oxidation resistance test and contact angle test. The new SiO2-Al203 inorganic amorphous sol sealing agent has good thermal stability. The SEM photos and porosity tests before and after sealing treatment show that the new type of inorganic amorphous sol sealing agent has good thermal stability. After sealing the pores, the porosity of the coating is obviously reduced, and the compactness of the coating is improved significantly. The SEM of the coating section and the distribution of the element surface show that the prepared Si02-Al203 sealing agent has excellent infiltration and sealing ability. The corrosion resistance of the coating before and after sealing is compared with that before and after sealing. The acid, alkali and salt corrosion resistance of the coating was improved by more than 50%, which enhanced the protective effect of the coating on the substrate. The high temperature oxidation resistance of the samples treated by sealing holes at 500 鈩，

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