Effect of Cr on oxidation of Ni-xAl alloy

【摘要】 The oxidation of the Ni-10Cr-xAl(x=7%,10%,molar fraction) alloys was studied at 1 100 ℃ under 0.1 MPa O2 and compared with that of the binary Ni-7Al and Ni-10Al alloys. The results show that the binary alloys form NiO external scales associated with an internal oxidation of Al. On the contrary,the ternary Ni-10Cr-7Al and Ni-10Cr-10Al form external alumina scale in contact with the alloy substrate. An addition of 10%Cr(molar fraction) into Ni-7Al and Ni-10Al inhibits the internal oxidation of aluminum and considerably reduces the critical content of Al needed to form exclusive alumina scales with respect to binary Ni-Al alloy,providing an example of third-element effect.更多还原

【Abstract】 The oxidation of the Ni-10Cr-xAl(x=7%,10%,molar fraction) alloys was studied at 1 100 ℃ under 0.1 MPa O2 and compared with that of the binary Ni-7Al and Ni-10Al alloys. The results show that the binary alloys form NiO external scales associated with an internal oxidation of Al. On the contrary,the ternary Ni-10Cr-7Al and Ni-10Cr-10Al form external alumina scale in contact with the alloy substrate. An addition of 10%Cr(molar fraction) into Ni-7Al and Ni-10Al inhibits the internal oxidation of aluminum and considerably reduces the critical content of Al needed to form exclusive alumina scales with respect to binary Ni-Al alloy,providing an example of third-element effect.更多还原