Segregation of Y to Grain Boundaries in Cr2 O 3 and NiO Scales Formed on an ODS Alloy
Segregation of Y to Grain Boundaries in Cr2 O 3 and NiO Scales Formed on an ODS Alloy
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DOI：
10.1149/1.2100264
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发表时间：
1987-10
影响因子：
3.9
通讯作者：
G. Yurek;K. Przybylski;A. Garratt-Reed
中科院分区：
文献类型：
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作者：
G. Yurek;K. Przybylski;A. Garratt-Reed
据报道[1，2]，Ni-Cr合金的抗氧化性在添加细Y2 O3颗粒的分散体时显著改善。本文报道了一种商用氧化物弥散强化合金MA 754（Ni-2 Owt % Cr-O）的氧化研究结果。3wt%的Al-O。5wt % Ti-O。MA 754合金是由约3vol %的Y_（203）颗粒（平均直径40 nm）与预合金粉末机械合金化而成。将该合金和二元Ni-24wt%Cr合金在1atm下在Ar-5%O2中在1000 - 1下氧化25小时。使用SEM和XRD对氧化皮进行了初步表征，结果表明在两种合金上均形成了多相氧化皮，这对于在IO 00 ~[3]下具有20-25wt% Cr的Ni合金是典型的。在合金晶界上形成的氧化皮主要是Cr2 O3，在氧化皮/气体界面处具有薄的富Ni氧化物层。在合金晶粒上，氧化皮包括NiO外层、Cr2 O3内层和含有NiCr 2 O的中间区域。对于MA 754，NiO和Cr2 O3层的厚度比为约1：1（~ 1. 7 μ m厚的Cr2 O3）和1：4的Ni-24 Cr（~ 8.6 μ m厚的Cr2 O3）。
It has been reported [1, 2] that the oxidation resistance of Ni-Cr alloys is improved considerably upon addition of a dispersion of fine Y203 particles. The object of this paper is to report the results of a study of the oxidation of a commercial, oxide-dispersionstrengthened alloy, MA754 (Ni-2Owt% Cr-O. 3wt% Al-O. 5wt% Ti-O. 6wt% Y203), and to demonstrate that the improved oxidation resistance of this alloy is due mainly to segregation of Y ions to grain boundaries in the Crz03 scale formed on its surface.Alloy MA754 is produced by mechanical alloying of about 3voi% of Y203 particles (40nm average diameter) with prealloyed powder. This alloy, and a binary Ni-24wt% Cr alloy, were oxidized for 25h at IO00~ in Ar-5% 02 at 1 atm. Initial characterization of the scales was performed using SEM and XRD, which demonstrated that multiphase oxide scales formed on both alloys, as is typical for alloys of Ni with 20-25wt% Cr at IO00~[3]. The scale that formed over alloy grain boundaries was mainly Cr203 with a thin layer of Ni-rich oxide at the scale/gas interface. Over alloy grains, the scales comprised an outer layer of NiO, an inner layer of Cr203, and an intermediate region that contained NiCr20,. The ratio of the thicknesses of the NiO and Cr203 layers was about I: I for the MA754 (~ l. 7um thick Cr203) and 1: 4 for the Ni-24Cr (~ 8.6 um thick Cr203).