Plasma and HVOF Spray of Colloidal Solutions to Create Nano-Scale Features in Coatings

胶体溶液的等离子和 HVOF 喷涂可在涂层中形成纳米级特征

• 批准号: 0456534
• 负责人: Rodney Trice
• 金额: --
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0456534&HistoricalAwards=false
• 关键词: Plasma; HVOF; Spray; Colloidal; Solutions

The objective of this research is to develop a novel injection technology that will allow quick and inexpensive fabrication of coatings comprised of nanoscale features. Virtually any material that can be dispersed in a solvent and that melts can be manufactured using this process. The approach is to disperse nanosized powders in a solvent to form a colloidal slurry, then spray the slurry into a plasma or a high velocity oxygen fuel (HVOF) generated plume to evaporate the solvent and melt the powder. The forward motion of the powders in the flame causes them to strike the substrate and flatten, forming nanosized "lamellae," which quickly solidify. The processing variables that control lamellae morphology and grain size, include slurry characteristics (powder size and powder loading in the solvent), injection nozzle style, plume type, and substrate temperature and type will be investigated. The resulting microstructure will be studied using X-ray diffraction, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Modeling of the impact and solidification behavior of these nanoscale droplets will be performed to compliment the experimental work.Thermal barrier coatings (TBCs), which protect the metallic structure in a gas turbine engine from temperature extremes, play an important role in the transportation (commercial aircraft) and energy (electricity generation) sectors of the U.S. economy. The use of TBCs allows gas turbines to be operated at higher, more fuel-efficient temperatures. By using the novel injection technology to prepare TBCs with nanocrystalline features it will be demonstrated that thermal conductivity can be significantly reduced as grain sizes approach phonon wavelengths. This will further increase the effectiveness of TBCs to protect the metallic structure of gas turbines. In conjunction with a special undergraduate research program established at the university, this proposal will provide engaging research opportunities for undergraduates.

这项研究的目的是开发一种新的注射技术，使快速和廉价的制备纳米级涂层成为可能。实际上，任何可以在溶剂中分散和熔化的材料都可以用这种方法制造。该方法是将纳米级粉末分散在溶剂中形成胶体浆料，然后将浆料喷射到等离子体或高速氧燃料（HVOF）产生的羽流中，使溶剂蒸发并熔化粉末。粉末在火焰中的向前运动使它们撞击基底并变平，形成纳米级的“薄片”，并迅速固化。控制薄片形态和晶粒尺寸的工艺变量，包括浆料特性（粉末尺寸和溶剂中的粉末含量）、喷嘴类型、羽流类型以及基材温度和类型，将被研究。所得的微观结构将使用x射线衍射、透射电子显微镜、原子力显微镜和扫描电子显微镜进行研究。模拟这些纳米液滴的冲击和凝固行为，以补充实验工作。热障涂层（tbc）保护燃气涡轮发动机的金属结构免受极端温度的影响，在美国经济的运输（商用飞机）和能源（发电）领域发挥着重要作用。tbc的使用允许燃气轮机在更高、更省油的温度下运行。通过使用新型注射技术制备具有纳米晶特征的tbc，将证明当晶粒尺寸接近声子波长时，热导率可以显着降低。这将进一步提高tbc保护燃气轮机金属结构的有效性。结合大学建立的一个特殊的本科生研究项目，该提案将为本科生提供引人入胜的研究机会。