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 Ni...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.展开更多
The effect of 5%Cr(mole fraction) on the scaling behavior of Ni-10Al was investigated at 900℃and 1 000℃with the aim to discuss the third element effect(TEE). The oxidation rate of the ternary alloy containing Cr is ...The effect of 5%Cr(mole fraction) on the scaling behavior of Ni-10Al was investigated at 900℃and 1 000℃with the aim to discuss the third element effect(TEE). The oxidation rate of the ternary alloy containing Cr is much slower than the corresponding binary alloys at both temperatures. A dense external scale of NiO overlying a zone of internal oxide precipitates forms on Ni-10Al, while Ni-5Cr-10Al develops a protective layer. So the addition of Cr promotes the formation of alumina scale. The possible mechanism of Cr on the oxidation of Ni-Al alloy is discussed.展开更多
通过同时加入Y和Ce获得了阻燃效果优异的Mg-Y-Ce阻燃镁合金,实现了镁合金在大气条件下的无保护熔炼,Mg-Y-Ce合金由工业纯Mg(99.9%,质量分数)、Mg-25%Y(质量分数)中间合金和纯Ce(99.5%,质量分数)在电阻炉中于保护性气氛(CO2+0.5%SF6)下...通过同时加入Y和Ce获得了阻燃效果优异的Mg-Y-Ce阻燃镁合金,实现了镁合金在大气条件下的无保护熔炼,Mg-Y-Ce合金由工业纯Mg(99.9%,质量分数)、Mg-25%Y(质量分数)中间合金和纯Ce(99.5%,质量分数)在电阻炉中于保护性气氛(CO2+0.5%SF6)下熔配而成。AES(PHI550 ESCA/SAM)和XRD(X’Pert Pro MPD)表面分析结果表明:当Mg-3Y-4.5Ce阻燃镁合金在高温下暴露于大气中时,其表面膜为双层膜,外层主要由Y2O3组成,而内层Y和Ce含量极低,以Mg和MgO为主。基于高温氧化热力学分析,建立了Mg-Y合金在高温下的选择性氧化模型,获得了Mg-Y合金能够发生选择性氧化的Y浓度阈值(约为7%,质量分数)。分析了Ce在Mg-Y合金选择性氧化中的第三元素效应,Ce起到了"吸气剂"的作用,可以抑制氧向合金内部扩散,从而抑制Y元素的内氧化。展开更多
基金Project(03206) supported by Shenyang Institute of Chemical Technology, ChinaProject(50571107) supported by the National Natural Scientific Foundation of China
文摘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.
基金Project(200603206) supported by the Shenyang Institute of Chemical Technology for PhD
文摘The effect of 5%Cr(mole fraction) on the scaling behavior of Ni-10Al was investigated at 900℃and 1 000℃with the aim to discuss the third element effect(TEE). The oxidation rate of the ternary alloy containing Cr is much slower than the corresponding binary alloys at both temperatures. A dense external scale of NiO overlying a zone of internal oxide precipitates forms on Ni-10Al, while Ni-5Cr-10Al develops a protective layer. So the addition of Cr promotes the formation of alumina scale. The possible mechanism of Cr on the oxidation of Ni-Al alloy is discussed.
文摘通过同时加入Y和Ce获得了阻燃效果优异的Mg-Y-Ce阻燃镁合金,实现了镁合金在大气条件下的无保护熔炼,Mg-Y-Ce合金由工业纯Mg(99.9%,质量分数)、Mg-25%Y(质量分数)中间合金和纯Ce(99.5%,质量分数)在电阻炉中于保护性气氛(CO2+0.5%SF6)下熔配而成。AES(PHI550 ESCA/SAM)和XRD(X’Pert Pro MPD)表面分析结果表明:当Mg-3Y-4.5Ce阻燃镁合金在高温下暴露于大气中时,其表面膜为双层膜,外层主要由Y2O3组成,而内层Y和Ce含量极低,以Mg和MgO为主。基于高温氧化热力学分析,建立了Mg-Y合金在高温下的选择性氧化模型,获得了Mg-Y合金能够发生选择性氧化的Y浓度阈值(约为7%,质量分数)。分析了Ce在Mg-Y合金选择性氧化中的第三元素效应,Ce起到了"吸气剂"的作用,可以抑制氧向合金内部扩散,从而抑制Y元素的内氧化。
