Self-Organized Hierarchically Rough Ceramic Coatings

自组织分级粗糙陶瓷涂层

• 批准号: RGPIN-2014-05419
• 负责人: Nychka, John
• 金额: $ 1.46万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=638154
• 关键词: Self; Organized; Hierarchically; Rough; Ceramic

A considerable worldwide research effort has been devoted to understanding the water spreading or repelling nature of solid surfaces (wettability). Early research in textiles and mineral processing identified surface roughness and chemistry as the only variables responsible for wetting behavior, and a plethora of processing strategies have since been attempted to produce hydrophilic and hydrophobic surfaces, coatings, and composites for applications where solid and liquid phases interact. Of the explored manufacturing techniques and materials an extreme minority, if any, are widespread, commercially viable, stable, or durable. The lack of success in achieving stability and durability has been due to the predominant use of polymers; polymers are soft, wear intolerant, susceptible to morphological changes under low to moderate heat and stress, and are not entirely chemically or light resistant. The shortcomings of current materials strategies will be addressed in this project through the coating of metallic substrates with ceramic materials (e.g., oxides, sulfides, nitrides, and carbides) for applications ranging from corrosion protection, steam generation and coatings for enhanced boiling heat transfer. This proposal will investigate and focus on the materials design, coating architecture, processing, and characterization of ceramic coatings on metallic substrates. Ceramic coatings have the potential to be harder, inert, stable, and durable with an appropriate manufacturing such as oxidation synthesis (heating a metal in laboratory air). The long-term engineering vision for this project is to discover a process whereby ceramic coatings can be manufactured in situ on a metallic surface in a self-organized fashion with inherent capability to tune their wettability through well-identified and controlled process variables. The research team (HQP) will be trained in and study, generation and dissemination of knowledge concerning the fundamental materials science and engineering challenges associated with creating ceramic coatings on metallic substrates. The three main program objectives are: 1) design, fabricate, and assess hierarchical roughness architectures for hydrophilic and hydrophobic response (pore structure and relative volume and interconnectedness, material selection, coating method, surface chemistry, hydroxyl content, C contamination, charge distribution). A variety of materials and coating systems will be investigated at this stage chosen by thermodynamic stability and compatibility; 2) characterization, phase identification, kinetics and thermodynamics analysis of ceramic component systems suitable for modeling and prediction of materials and coating performance (crystallography, surface wettability under varying relative humidity and temperature); 3) subject materials system to high temperature and moist environments to assess and prevent, through materials, processing, and coating architecture design, any deleterious structural evolution leading to topological, or surface chemistry changes alter wettability (microscopy, roughness changes, contamination, phase separation, and associated apparent contact angle changes). Coating techniques which can control both surface topography and chemistry will be investigated: 1) Oxidation Synthesis whereby coatings will be grown through reaction with gaseous environments to produce rough crystallites; 2) Sol-Gel Processing whereby a rough coating from oxidation synthesis will be coated with a ceramic of low polar surface free energy (rare earth oxides) which will also be rough; and 3) Spinodal Decomposition whereby ceramic coatings will decompose to produce rough coatings. Impact will be widespread and seen in many industries from corrosion control to energy production.

全球范围内进行了大量的研究工作，致力于了解固体表面的水扩散或排斥性质（润湿性）。纺织品和矿物加工的早期研究确定表面粗糙度和化学是影响润湿行为的唯一变量，此后尝试了大量的加工策略来生产亲水和疏水表面、涂层和复合材料，用于固相和液相相互作用的应用。在所探索的制造技术和材料中，极少数（如果有的话）是广泛使用的、商业上可行的、稳定的或耐用的。由于主要使用聚合物，在实现稳定性和耐用性方面缺乏成功；聚合物质地柔软，不耐磨损，在中低热和应力下容易发生形态变化，并且不完全耐化学或耐光。该项目将通过在金属基材上涂覆陶瓷材料（例如氧化物、硫化物、氮化物和碳化物）来解决当前材料策略的缺点，其应用范围包括腐蚀防护、蒸汽发生和增强沸腾传热的涂层。该提案将研究并重点关注金属基材上陶瓷涂层的材料设计、涂层结构、加工和表征。通过氧化合成（在实验室空气中加热金属）等适当的制造，陶瓷涂层有可能变得更硬、惰性、稳定和耐用。该项目的长期工程愿景是发现一种工艺，使陶瓷涂层能够以自组织方式在金属表面上原位制造，并具有通过明确识别和控制的工艺变量来调节其润湿性的内在能力。研究团队（HQP）将接受培训，研究、生成和传播与在金属基材上创建陶瓷涂层相关的基本材料科学和工程挑战的知识。三个主要计划目标是：1）设计、制造和评估亲水和疏水响应的分层粗糙度结构（孔隙结构和相对体积和互连性、材料选择、涂层方法、表面化学、羟基含量、碳污染、电荷分布） 。现阶段将研究各种材料和涂层系统，通过热力学稳定性和相容性进行选择； 2）适用于材料和涂层性能（晶体学、不同相对湿度和温度下的表面润湿性）建模和预测的陶瓷组件系统的表征、相识别、动力学和热力学分析； 3) 将材料系统置于高温和潮湿的环境中，通过材料、加工和涂层结构设计来评估和防止任何导致拓扑或表面化学变化改变润湿性的有害结构演变（显微镜检查、粗糙度变化、污染、相分离） ，以及相关的表观接触角变化）。将研究可以控制表面形貌和化学性质的涂层技术：1）氧化合成，通过与气体环境反应生成粗糙的微晶来生长涂层； 2) 溶胶-凝胶处理，其中氧化合成的粗糙涂层将被涂上低极性表面自由能（稀土氧化物）的陶瓷，该陶瓷也将是粗糙的； 3) 旋节线分解，陶瓷涂层分解产生粗糙涂层。影响将是广泛的，并会出现在从腐蚀控制到能源生产的许多行业中。