Phase composition, structural, and plasma erosion properties of ceramic coating prepared by suspension plasma spraying

Y3Al5O12 (YAG), Y2O3, and Al2O3 ceramic coatings were manufactured to investigate the plasma erosion properties. The X-Ray Diffraction (XRD) analysis confirmed that YAG coating was synthesized successfully by Y2O3 and Al2O3 mixture suspension using the plasma spraying method. Meanwhile, metastable phases were found in Y2O3 and Al2O3 coatings due to the quenching in cooling process of melted droplets. The coating surface morphology and microstructure of cross sections were characterized by SEM. The results reveal that coatings are composed by ultrafine splats and exhibit dense lamellar structure. The plasma erosion properties were evaluated at different etching test power under Ar/CF4/O-2 plasma gas. The experimental results clarify that both of YAG and Y2O3 coatings show the better plasma erosion resistance than Al2O3 coatings. The formation of fluorination layer surface prevents the coatings from further erosion with plasma gas. Moreover, the etching rate of coatings depended on the fluorination and removing rate of fluoride layer.