Mechanical and thermal properties and plasma etching mechanism of Y–Al–O based ceramics under NF ₃ /Ar and Cl ₂ /Ar plasma

Abstract Mechanical properties, thermal properties, and plasma irradiation behavior under NF 3 /Ar and Cl 2 /Ar plasma of Y–Al–O based ceramics (YAG, YAP, and YAM) were studied. The mechanical properties such as bending strength, Vickers hardness, fracture toughness, and elastic modulus of YAP were superior to those of Y 2 O 3 . Cross-sectional scanning transmission electron microscope-energy dispersive X-ray spectrometer and thermodynamic analysis revealed that the etching mechanism of Y–Al–O based ceramics was different between the two plasma environment; under NF 3 /Ar plasma, the formation and removal rate of the fluorinated alteration layer was comparable, whereas under Cl 2 /Ar plasma, the removal rate of the chlorinated layer was lower than its formation rate, suggesting a highly etch-resistant alteration layer. Among the Y–Al–O based ceramics, YAM exhibited the smallest surface roughness change under both plasma conditions, indicating superior plasma etching resistance. These results suggest that YAM is a promising candidate as a plasma-resistant ceramic to replace Y 2 O 3 .