New design concept for stableα-silicon nitride based on the initial oxidation evolution at the atomic and molecular levels

作     者：Chunyu Guo Enhui Wang Zhi Fang Yapeng Zheng Tao Yang Zhijun He Xinmei Hou Chunyu Guo;Enhui Wang;Zhi Fang;Yapeng Zheng;Tao Yang;Zhijun He;Xinmei Hou

作者机构：Beijing Advanced Innovation Center for Materials Genome EngineeringCollaborative Innovation Center of Steel TechnologyUniversity of Science and Technology BeijingBeijing 100083China The State Key Laboratory of Refractories and MetallurgyWuhan University of Science and TechnologyWuhan 430081China School of Materials and MetallurgyUniversity of Science and Technology LiaoningAnshan 114051China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第122卷第27期

页      面：156-164页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financially supported by the National Science Fund for Distinguished Young Scholars(No.52025041) the National Natural Science Foundation of China(Nos.51904021,51974021,51902020) the Fundamental Research Funds for the Central Universities(No.FRF-TP-19-008A1) the State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology(No.G202003) 

主　　题：α-Si_(3)N_(4) Surface oxidation Nitrogen vacancy DFT MD 

摘      要：As the dominated composition of Si_(3)N_(4)ceramics,α-silicon nitride(α-Si_(3)N_(4))can satisfy the strength and fracture toughness demand in the ***,α-Si_(3)N_(4)is oxygen-sensitive at high temperatures,which limits its high-temperature *** improve the oxidation resistance ofα-Si_(3)N_(4)ceramics,it is necessary to shed light on the oxidation ***,the initial oxidation ofα-Si_(3)N_(4)was systematically studied at the atomic and molecular *** density functional theory(DFT)calculation denotes that the(001)surface ofα-Si_(3)N_(4)has the best stability at both room temperature and high ***,the oxidation process of theα-Si_(3)N_(4)(001)surface consists of O adsorption and N desorption,and the consequent formation of nitrogen-vacancy(VN)is the key step for further ***,the molecular dynamics(MD)simulation indicates that the oxidation rate ofα-Si_(3)N_(4)(100)surface is slower than that ofα-Si_(3)N_(4)(001)surface due to the lower N concentration at the outermost ***,the oxidation resistance ofα-Si_(3)N_(4)can be improved by regulating the(100)surface as the dominant exposure *** addition,reducing the concentration of N on the final exposed surface ofα-Si_(3)N_(4)by mean of constructing the homojunction of the Si-terminal(100)surface and other N-containing surfaces(such as(001)surface)should be also a feasible approach.