High-throughput reaction engineering to assess the oxidation stability of MAX phases
High-throughput reaction engineering to assess the oxidation stability of MAX phases
复制标题
高通量反应工程评估 MAX 相的氧化稳定性
DOI：
10.1038/s41524-020-00464-7
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发表时间：
2021-01-04
影响因子：
9.7
通讯作者：
Arroyave, R.
中科院分区：
文献类型：
--
作者：
Sauceda, D.;Singh, P.;Arroyave, R.
某些M（n+1）AX（n）（MAX）相所表现出的对氧化环境的耐受性源于在高操作温度下形成稳定且保护性的氧化物层。MAX相是具有通式M（n+1）AX（n），n=1，2，3的六方排列的层状氮化物或碳化物，其中M是前过渡元素，A是A块元素，并且X是C/N。由于较高的计算成本，先前对这些系统中的氧化物相稳定性进行建模和评估的尝试在范围上受到限制。为了解决这个问题，我们开发了一个机器学习驱动的高通量框架，用于快速评估211 chemistry MAX phase M（2）AX的相稳定性和氧反应性。所提出的方案结合了一个确定的独立筛选稀疏化算子为基础的机器学习模型与巨正则线性规划相结合，以评估温度相关的吉布斯自由能，反应产物和元素的化学活性在氧化的MAX阶段。为了了解Ti 2AlC的高温氧化行为，对Ti 2AlC的热力学稳定性和组成元素对氧的化学活性进行了全面的评估。的预测是在良好的协议与氧化实验上进行Ti 2AlC。我们还能够解释Ti 2SiC的亚稳性，由于竞争相的更高稳定性，Ti 2SiC不能通过实验合成。对于所提出的方法的一般性，我们讨论了Cr2 AlC的氧化机制。对氧化行为的深入了解将使得能够更有效地设计和加速MAX相的发现，同时在高温氧化环境中保持性能。
The resistance to oxidizing environments exhibited by some M(n+1)AX(n) (MAX) phases stems from the formation of stable and protective oxide layers at high operating temperatures. The MAX phases are hexagonally arranged layered nitrides or carbides with general formula M(n+1)AX(n), n=1, 2, 3, where M is early transition elements, A is A block elements, and X is C/N. Previous attempts to model and assess oxide phase stability in these systems has been limited in scope due to higher computational costs. To address the issue, we developed a machine-learning driven high-throughput framework for the fast assessment of phase stability and oxygen reactivity of 211 chemistry MAX phase M(2)AX. The proposed scheme combines a sure independence screening sparsifying operator-based machine-learning model in combination with grand-canonical linear programming to assess temperature-dependent Gibbs free energies, reaction products, and elemental chemical activity during the oxidation of MAX phases. The thermodynamic stability, and chemical activity of constituent elements of Ti2AlC with respect to oxygen were fully assessed to understand the high-temperature oxidation behavior. The predictions are in good agreement with oxidation experiments performed on Ti2AlC. We were also able to explain the metastability of Ti2SiC, which could not be synthesized experimentally due to higher stability of competing phases. For generality of the proposed approach, we discuss the oxidation mechanism of Cr2AlC. The insights of oxidation behavior will enable more efficient design and accelerated discovery of MAX phases with maintained performance in oxidizing environments at high temperatures.