Non‐equimolar multi‐principal element monosilicates with excellent corrosion resistance

Abstract Achieving an excellent corrosion resistance against calcium‐magnesium aluminosilicate (CMAS) molten salt in multi‐principal element monosilicates (( n RE xi ) 2 SiO 5 ) presents a critical challenge. Herein, a non‐equimolar rare earth elements (REEs) design approach was proposed, and ten variants of ( n RE xi ) 2 SiO 5 with three to five components were synthesized to investigate their CMAS corrosion resistance. The findings indicate that corrosion resistance is substantially influenced by the ionic radii of REEs, impacting corrosion behaviors from both thermodynamic and kinetic points of view. On the basis of these insights, a methodology for designing non‐equimolar ( n RE xi ) 2 SiO 5 materials with enhanced resistance to CMAS corrosion at temperatures up to 1500°C is proposed.