摘要
利用TGA,SEM／EDS研究了Ag含量对β-NiAl合金高温氧化时生成Al2O3膜表面形貌的影响及添加1％Ag(原 子分数)对1000℃氧化动力学的影响.结果表明, β-NiAl合金的氧化动力学由两段抛物线组成,分别受亚稳Al2O3和稳态 α-Al2O3的生长控制. NiAl-1Ag合金的氧化动力学由三段抛物线组成,分别受γ-Al2O3,θ-Al2O3和α-Al2O3的生长 控制. 1000℃时,向β-_NiAl中添加少量的Ag(<1％)可以促进亚稳Al2O3向稳态α-Al2O3的转变.当添加量超过5％ 时,促进作用不明显. 1100℃时,添加0.5％Ag对Al2O3的相变无明显的促进作用.
The effect of adding small amounts of Ag (0.5%, 1%, 5% and 10%, atomic fraction) to β-NiAl on surface morphology of alumina scale during the oxidation at 1000-1100°C and the oxidation kinetics of β-NiAl and NiAl-1Ag were investigated by TGA and SEM/EDS. The kinetics of β-NiAl presents two parabolic stages controlled by the growth of metastable alumina and stable α-Al2O3, respectively, while the kinetics of NiAl-1Ag is composed of three different parabolic stages controlled by the growth of γ-Al2O3, θ-Al2O3 and α-Al2O3, respectively. The addition of small amounts of Ag ( less than or equal 1%) to β-NiAl favors the phase transformation from metastable alumina to α-Al2O3, while this effect disappears for an Ag content above 5% at 1000°C oxidation. Finally, the addition of 0.5% Ag to β-NiAl does not affect the surface morphology of Al2O3 at 1100°C.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第4期369-374,共6页
Acta Metallurgica Sinica
基金
国家自然科学基金资助项目50271079
