A novel and facile solvothermal fluorination approach for boosting oxidation resistance of TiAl alloy

Abstract

A novel and facile solvothermal fluorination treatment was applied for the first time to incorporate fluorine into γ-TiAl alloys via a straightforward one-step procedure. It exhibits significant advantages of cost-effectiveness and operational simplicity. Oxidation tests revealed that fluorination prevents oxidation progression and spallation by forming a continuous Al₂O₃ layer. Under optimized solvothermal conditions, the mass gain of the fluorinated sample is only 7.7 % of that of the untreated γ-TiAl. The reaction between aluminum fluoride and oxygen promotes the formation of AlOF while the titanium fluoride sublimates and disappears, which subsequently reacts with oxygen to generate the protective Al₂O₃ layer. Ultimately, this compact Al₂O₃ layer efficiently prevents the inward diffusion of oxygen and outward diffusion of alloy elements.