报告人：Dr. Lee Sung-Min 

　　　　Dr. Oh Yoon-suk 

　　　　Korea Institute of Ceramic Engineering and Technology, KOREA 

时间：2018年12月20日（周四）10:00-12:00 

地点：李薰楼468会议室

报告1：Ceramics for Fluorine-based Plasma Environment: Erosion Mechanism and New Plasma Resistant Materials

Abstract：In semiconductor manufacturing equipment, the ceramics are exposed to fluorine- or chlorine-based plasma, experiencing erosion due to the interaction with the plasmas as well as producing particulate contaminations. Through high precision X-ray photoelectron spectroscopy, the surface of the ceramics was found to consist of a nanometer thin top C-F polymer layer and the underlying fluorinated oxide layer which is thermodynamically stable. Thus, this result support that erosion of Al₂O₃ and Y₂O₃ ceramics under fluorocarbon plasma occurs by a physical removal process with simultaneous surface fluorination which was induced by the interaction with plasma. In these regards, a new dense Y₂O₃ coating is being studied using several techniques, including physical vapor deposition, aerosol deposition, and suspension plasma spray (SPS). Of these, suspension plasma spray could possibly provide dense Y₂O₃, which could contribute to reducing contamination particles. In addition to oxides, a new oxyfluoride material with various F content are being developed.

报告2：Ytterbium Silicate based EBC development by Suspension Plasma Spray

Abstract：SiC-based CMCs are attracting attention as hot section parts in airfoil engine at high-temperature operation environment. However, there is a disadvantage that the lifetime is shortened in a high temperature oxidizing and moisture atmosphere. To overcome this, an environmental shielding coating is being studied. In this study, we tried to fabricate an environmentally shielding coating using Yb₂Si₂O₇ which is excellent in oxidation resistance and has similar thermal expansion coefficient with SiC by suspension plasma spray. In order to prepare a crystalline Yb₂Si₂O₇ coating layer, the gas concentration of the plasma spray was adjusted and 2 types of solvent used for the suspension manufacturing with several mixing ratios. The prepared coating samples are analyzed by X-ray diffraction, scanning electron microscope, transmission electron microscopes, and energy dispersive X-ray spectroscopy for phase and microstructure change. Highly crystalline ytterbium disilicate is observed at low plasma enthalpy with no hydrogen gas and 20% addition of water in ethanol suspension.