Abstract Many industrial applications require hydrophobic surfaces with high-temperature compatibility. Ceramic surfaces, which have excellent endurance for high-temperature, are generally hydrophilic. For such applications, the required hydrophobicity is induced in ceramic surfaces with suitable polymeric agents by using different surface grafting techniques. To avoid the costly grafting process, suitable hydrophobic ceramic surfaces have to be designed for direct use in such applications. Rare earth oxides show hydrophobicity due to their electronic configurations. Hence, for the selection of hydrophobic ceramic material for real engineering components, three plasma spray-coated surfaces have been characterized for their water contact angle. In this study, yttria (Y2O3) was used as a rare earth oxide along with yttria stabilized zirconia (YSZ) and alumina (Al2O3) for comparison of surface properties. The dependence of contact angle on various experimental parameters was established. It was observed that cleaning with water induces temporary hydrophobicity in alumina even after baking at 180 °C. Yttria coating was found to be distinctly hydrophobic with the contact angle more than 115°. The hydrophobic behaviour of yttria was found to be permanent and does not degrade with environmental exposure. The apparent surface energies of the samples were estimated based on acid-base theory. The apparent surface energies of the studied samples were found to be in the range of 35 mJ/m2 to 42 mJ/m2.

中文翻译：

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等离子喷涂氧化物陶瓷疏水性润湿性研究

摘要 许多工业应用需要具有高温相容性的疏水表面。陶瓷表面具有优异的耐高温性，通常是亲水的。对于此类应用，通过使用不同的表面接枝技术，用合适的聚合物试剂在陶瓷表面诱导所需的疏水性。为了避免昂贵的接枝过程，必须设计合适的疏水陶瓷表面以直接用于此类应用。稀土氧化物由于其电子构型而显示出疏水性。因此，为了为实际工程部件选择疏水性陶瓷材料，三个等离子喷涂表面的水接触角已被表征。在这项研究中，氧化钇 (Y2O3) 与氧化钇稳定氧化锆 (YSZ) 和氧化铝 (Al2O3) 一起用作稀土氧化物，用于比较表面特性。建立了接触角对各种实验参数的依赖性。据观察，即使在 180 °C 下烘烤后，用水清洗也会导致氧化铝暂时疏水。发现氧化钇涂层明显疏水，接触角大于 115°。发现氧化钇的疏水行为是永久性的并且不会随着环境暴露而降解。基于酸碱理论估计样品的表观表面能。发现所研究样品的表观表面能在 35 mJ/m2 至 42 mJ/m2 的范围内。建立了接触角对各种实验参数的依赖性。据观察，即使在 180 °C 下烘烤后，用水清洗也会导致氧化铝暂时疏水。发现氧化钇涂层明显疏水，接触角大于 115°。发现氧化钇的疏水行为是永久性的并且不会随着环境暴露而降解。基于酸碱理论估计样品的表观表面能。发现所研究样品的表观表面能在 35 mJ/m2 至 42 mJ/m2 的范围内。建立了接触角对各种实验参数的依赖性。据观察，即使在 180 °C 下烘烤后，用水清洗也会导致氧化铝暂时疏水。发现氧化钇涂层明显疏水，接触角大于 115°。发现氧化钇的疏水行为是永久性的并且不会随着环境暴露而降解。基于酸碱理论估计样品的表观表面能。发现所研究样品的表观表面能在 35 mJ/m2 至 42 mJ/m2 的范围内。发现氧化钇的疏水行为是永久性的并且不会随着环境暴露而降解。基于酸碱理论估计样品的表观表面能。发现所研究样品的表观表面能在 35 mJ/m2 至 42 mJ/m2 的范围内。发现氧化钇的疏水行为是永久性的并且不会随着环境暴露而降解。基于酸碱理论估计样品的表观表面能。发现所研究样品的表观表面能在 35 mJ/m2 至 42 mJ/m2 的范围内。