Hot corrosion behavior of multialkaline-earth aluminosilicate for environmental barrier coatings

Multialkaline-earth aluminosilicate Ba1/3Sr1/3Ca1/3Al2Si2O8 (BSCAS) were synthesized to serve as new envi-ronment barrier coatings. Their hot corrosion behavior in an Na2SO4 environment was studied in the temper-ature range of 900-1100 degrees C over a period of 100 h. The phase and cross-sectional morphology evolutions of the corroded samples were characterized via X-ray diffraction and scanning electron microscopy. Combined with the thermodynamic analysis of the possible reactions occurring during hot corrosion, the competitive out-diffusion of the alkaline-earth elements to react with Na2SO4 is believed to have a considerable influence on the hot corrosion behavior of BSCAS. The sluggish diffusion and the dense Ca2Al2SiO7 layer, which originate from the competitive reactions of the multialkaline earth elements, lead to an improvement in the hot corrosion resistance of BSCAS. A model is proposed to describe the hot corrosion process.

Automated summary

The hot corrosion behavior of multialkaline-earth aluminosilicate Ba1/3Sr1/3Ca1/3Al2Si2O8 (BSCAS) in an Na2SO4 environment at temperatures ranging from 900 to 1100 degrees C over a period of 100 hours was studied. The phase and cross-sectional morphology evolutions of the corroded samples were characterized using X-ray diffraction and scanning electron microscopy. The competitive out-diffusion of alkaline-earth elements and the formation of a dense Ca2Al2SiO7 layer contribute to the improvement in the hot corrosion resistance of BSCAS.