Pool boiling fouling and corrosion properties on liquid‐phase‐deposition TiO2 coatings with copper substrate
Pool boiling fouling and corrosion properties on liquid‐phase‐deposition TiO2 coatings with copper substrate
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DOI：
10.1002/aic.12405
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发表时间：
2011-07
期刊：
影响因子：
3.7
通讯作者：
Li Wang;Mingyan Liu
中科院分区：
文献类型：
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作者：
Li Wang;Mingyan Liu
工业热交换器的传热表面上的污垢是一个棘手的问题，并且已经提出了几种技术来抑制污垢。表面涂层是一种通过低表面自由能薄膜来降低污垢与传热表面之间的粘附力的技术。本文采用液相沉积法在紫铜基体上制备了微米级或纳米级的二氧化钛薄膜。涂层厚度，接触角，粗糙度，表面形貌，和组件进行了测量与X射线衍射，接触角分析仪，针式粗糙度，扫描电子显微镜，和能量色散X射线光谱仪，分别。基于接触角计算了涂层的表面自由能。研究了蒸馏水和碳酸钙溶液在涂层表面池沸腾的传热和污垢特性。与未处理或抛光的表面相比，在涂覆的表面上观察到传热增强，这是由于微结构和纳米结构的表面可能增加成核位点的数量。由于涂层表面的表面自由能降低，涂层表面的不结垢时间比未处理或抛光表面的不结垢时间延长。定性地探讨了涂层表面在室温下浸泡在高浓度盐酸、氢氧化钠和氯化钠盐溶液中数小时后的腐蚀行为。获得了涂层表面的防腐蚀结果。涂层耐碱性腐蚀时间为7.2 × 105s，耐酸性腐蚀时间为3.6 × 105s，耐盐性腐蚀时间为2.16 × 106s。本研究为避免工业蒸发器传热表面的污垢沉积和腐蚀开辟了一条新的涂层途径，对相关行业的节能降耗具有重要意义。© 2010美国化学工程师学会AIChE J，2011
Fouling on the heat transfer surfaces of industrial heat exchangers is an intractable problem, and several techniques have been suggested to inhibit fouling. Surface coatings are of such techniques by which the adhesion force between fouling and heat transfer surface can be reduced with low surface free energy thin films. In this article, liquid phase deposition was applied to coat titanium dioxide thin films on the red copper substrates with film thickness in micro- or nano-meter scale. Coating thickness, contact angle, roughness, surface topography, and components were measured with X-ray diffraction, contact angle analyzer, stylus roughmeter, scanning electron microscopy, and energy dispersive X-ray spectroscopy, respectively. Surface free energy of coating layers was calculated based on the contact angle. Heat transfer and fouling characteristics in pool boiling of distilled water and calcium carbonate solution on coated surfaces were investigated. Heat transfer enhancement was observed on coated surfaces compared with untreated or polished surfaces due to the micro- and nano-structured surfaces which may increase the number of nucleation sites. The nonfouling time on the coated surfaces is extended than that on the untreated or polished surfaces due to the reducing of the surface free energy of coated surfaces. Corrosion behavior of coated surfaces soaked in the corrosive media of hydrochloric acid, sodium hydroxide alkali, and sodium chloride salt solutions with high concentration at room temperature a few hours was also explored qualitatively. Anticorrosion results of the coated surfaces were obtained. The coatings resisted alkali corrosion within 7.2 × 105 s, acidic corrosion within 3.6 × 105 s and salt corrosion within 2.16 × 106 s. The present work may open a new coating route to avoid fouling deposition and corrosion on the heat transfer surfaces of industry evaporators, which is very important for energy saving in the related industries. © 2010 American Institute of Chemical Engineers AIChE J, 2011