The influence of CrTaO4 layer on the oxidation behavior of a directionally-solidified nickel-based superalloy at 850-900 degrees C
The influence of CrTaO4 layer on the oxidation behavior of a directionally-solidified nickel-based superalloy at 850-900 degrees C
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CrTaO4层对定向凝固镍基高温合金850~900℃氧化行为的影响
DOI：
10.1016/j.jallcom.2017.07.066
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发表时间：
2017
影响因子：
6.2
通讯作者：
Zhou Lanzhang
中科院分区：
文献类型：
--
作者：
Ren Weili;Ouyang Fenfen;Ding Biao;Zhong Yunbo;Yu Jianbo;Ren Zhongming;Zhou Lanzhang
研究了在850 ~ 900℃温度下，不同时间间隔（最长时间为300 h）下，crtao4对镍基合金定向凝固氧化行为的影响。氧化层由三层组成。外层主要由Cr2O3、TiO2和NiCr2O4组成，中间层为CrTaO4，内氧化层主要由Al2O3组成。经过一定时间的氧化，形成连续的crtao4层。随着温度的升高，连续层的形成时间缩短。此外，该层使氧化动力学由抛物定律转变为三次定律。当建立连续的crtao4层时，氧化过程的控制由Cr、Ti、Ni向外扩散转变为O向内扩散。从氧化动力学角度阐明了Ta对ni基高温合金氧化行为的影响机理。
The influence of CrTaO4on the oxidation behavior of a directionally solidified nickel-based alloy has been investigated at the temperatures between 850 °C and 900 °C for the different time intervals (the longest time is 300 h). The oxide scale consists of three layers. The outer layer is mainly composed of Cr2O3, TiO2, and NiCr2O4, the middle layer is CrTaO4, and the inner oxide layer mainly consists of Al2O3. The continuous CrTaO4layer is formed after oxidation for certain times. The formation time of continuous CrTaO4layer shortens with the temperature increase. Furthermore, the layer causes the transformation of the oxidation kinetics from the parabolic law to the cubic law. The control of oxidation process converts from the outward diffusion of Cr, Ti, and Ni to the inward diffusion of O when the continuous CrTaO4layer is established. The mechanism clarifies the influence of Ta on the oxidation behavior of Ni-based superalloys from the oxidation kinetics.