CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close ...CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close thermal expansion coefficient(TEC)to RHEAs.These appealing properties enable CrTaO_(4)as a new type of protective scale material for high-temperature applications such as in air breathing jet engines.For such engine applications,CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)corrosion is a critical issue.However,the corrosion behavior of CrTaO_(4)under CMAS attack remains unknown so far.Here,the corrosion resistance of CrTaO_(4)to molten CMAS is comprehensively studied.It is demonstrated that the CMAS corrosion resistance is significantly superior over commercial yttria-stabilized zirconia and the commonly investigated thermal barrier coating materials.Element and phase compositional analyses indicate dense and CMAS corrosion-resistant layers are established between CMAS and the CrTaO_(4)substrate.The interface reaction between the CrTaO_(4)substrate and CMAS at 1250 and 1300℃gives rise to a dense layer composed of CaTa_(2)O_(6) and Mg(Cr,Al)_(2)O_(4)spinel just beneath the molten CMAS.At 1350℃,a phase composition gradient layer,composed of crystalline phases CaTa_(2)O_(6)/CaTa_(2)O_(6)+Mg(Cr,Al)_(2)O_(4)/CaTa_(2)O_(6)+Cr2O_(3),is formed.With increased calcium consumption due to more Ca-containing crystalline phase formation upon elevating temperature,the Ca/Si ratio in CMAS melt declines,thereby increasing the viscosity of the melt and mitigating the penetration of CMAS into the CrTaO_(4)substrate.展开更多
基金supported by the National Natural Science Foundation of China(Nos.U23A20562 and 52302074).
文摘CrTaO_(4)has been found to play a pivotal role in the protection of refractory high-entropy alloys(RHEAs)from high-temperature oxidation and thermal attack due to its high melting point,low thermal conductivity,close thermal expansion coefficient(TEC)to RHEAs.These appealing properties enable CrTaO_(4)as a new type of protective scale material for high-temperature applications such as in air breathing jet engines.For such engine applications,CaO-MgO-Al_(2)O_(3)-SiO_(2)(CMAS)corrosion is a critical issue.However,the corrosion behavior of CrTaO_(4)under CMAS attack remains unknown so far.Here,the corrosion resistance of CrTaO_(4)to molten CMAS is comprehensively studied.It is demonstrated that the CMAS corrosion resistance is significantly superior over commercial yttria-stabilized zirconia and the commonly investigated thermal barrier coating materials.Element and phase compositional analyses indicate dense and CMAS corrosion-resistant layers are established between CMAS and the CrTaO_(4)substrate.The interface reaction between the CrTaO_(4)substrate and CMAS at 1250 and 1300℃gives rise to a dense layer composed of CaTa_(2)O_(6) and Mg(Cr,Al)_(2)O_(4)spinel just beneath the molten CMAS.At 1350℃,a phase composition gradient layer,composed of crystalline phases CaTa_(2)O_(6)/CaTa_(2)O_(6)+Mg(Cr,Al)_(2)O_(4)/CaTa_(2)O_(6)+Cr2O_(3),is formed.With increased calcium consumption due to more Ca-containing crystalline phase formation upon elevating temperature,the Ca/Si ratio in CMAS melt declines,thereby increasing the viscosity of the melt and mitigating the penetration of CMAS into the CrTaO_(4)substrate.
