Erosion Behavior of YAG Ceramics under Fluorine Plasma and their XPS Analysis

Chemical composition and status of chemical bonding of the YAG(Y3Al5O12) ceramics after the exposure to fluorine plasma have been investigated using X-ray photoelectron spectroscopy, with the analysis on its erosion behavior. On the surface, F showed the maximum content, decreasing with depth, meanwhile the cation composition remained almost constant, irrespective of the position. The peaks due to Y in the reaction layer consisted of two kinds, showing the Y-O and Y-F bonds. These surface modifications under fluorine plasma seem to promote the erosion of the YAG ceramics. Excess addition of Al2O3 or Y2O3 into stoichiometric YAG produced 2nd phases of Al2O3 and YAlO3, respectively, resulting in the slight difference in the local erosion rates. But, the overall average erosion rate was not sensitive to such excess additions of Al2O3 or Y2O3.