General trends in surface stability and oxygen adsorption behavior of transition metal diborides (TMB2)

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2019,（4）
• 页码范围: 584-590
• 页数: 7页
• 语种: 英文

摘要

The potential applications of transition metal diborides (TMB2) in extreme environments are particularly attractive but still blocked by some intrinsic properties such as poor resistances to thermal shock and oxidation.Since surface plays a key role during grain growth and oxygen adsorption,an insight into the surface properties of TMB2 is essential for understanding the materials performance and accelerating the development of ultra-high temperature ceramics,By employing two-region modeling method,the stability and oxygen adsorption behavior of TMB2 surfaces were investigated by first-principles calculations based on density functional theory.The effects of valance electron concentration on the surface stability and oxygen adsorption were studied and the general trends were summarized.After analyzing the anisotropy in surface stability and oxygen adsorption,the observed grain morphology of TMB2 were well explained,and it was also predicted that YB2,HfB2 and TaB2 may have better initial oxidation resistance than ZrB2.