文章信息/Info

Title:

Interactions of Carbon and Hydrogen Interstitial Atoms in LaNi5: A First-Principles Study

文章編號(hào):

1674-3962(2025)12-1162-06

作者:

向鑫; 楊飛龍; 胡立; 宋雅琪; 朱宏志

中國(guó)工程物理研究院材料研究所，四川 江油 621908

Author(s):

XIANG Xin; YANG Feilong; HU Li; SONG Yaqi; ZHU Hongzhi

Institute of Materials，China Academy of Engineering Physics，Jiangyou 621908，China

關(guān)鍵詞:

LaNi5; 間隙原子; 相互作用; 第一性原理

Keywords:

LaNi5; interstitial atom; interaction; first-principles

分類號(hào):

TG139+.7

DOI:

10.7502/j.issn.1674-3962.202406007

文獻(xiàn)標(biāo)志碼:

A

摘要:

LaNi5合金因其優(yōu)良的綜合性能，如吸氫容量大、吸/放氫快、平衡離解壓適中等，在氫能及氫同位素工藝等領(lǐng)域得到了廣泛的應(yīng)用。然而，LaNi5合金中間隙雜質(zhì)如C、H等的相互作用機(jī)制尚不明確。采用第一性原理計(jì)算研究了LaNi5中C、H間隙原子的占位、形成能、遷移行為及二者間的相互影響。從形成能及原子構(gòu)型來看，LaNi5中C、H原子的穩(wěn)定占位分別是2d和12n間隙位。因原子半徑更小及更低的形成能和遷移勢(shì)壘，LaNi5中間隙H原子比間隙C原子更易形成和遷移。LaNi5中C、H間隙原子間存在明顯的相互作用。具體來講，LaNi5中的間隙C、H原子將分別因H、C原子的引入更易形成，但其遷移能力將變差。上述研究結(jié)果對(duì)LaNi5合金中C雜質(zhì)的提純、控制及含C雜質(zhì)氣體形成機(jī)理的認(rèn)識(shí)有重要的指導(dǎo)意義。

Abstract:

LaNi5 alloys are widely used in the fields of hydrogen energy and hydrogen isotope technology for their excellent comprehensive performances, such as high hydrogen absorption capacity, fast absorption/desorption kinetics, moderate equilibrium dissociation pressure, etc. However, the interaction mechanism of interstitial impurities such as C and H in LaNi5 is still unclear. The occupancy, formation energies, migration behaviors of C and H interstitial atoms and interactions between C and H interstitial atoms in LaNi5 have been thus investigated via first-principles calculations. From the view of formation energy and atomic configuration, the stable occupying site of C and H interstitial atoms in LaNi5 is 2d and 12n site, respectively. An interstitial H atom is more readily to form and migrate than C in LaNi5 for its smaller atomic size, and much lower formation energy and migration barrier. Obvious interactions between C and H interstitial atoms present in LaNi5. Specifically, the C or H interstitial atom in LaNi5 is more readily to form separately with the addition of H or C atom, while the individual migration ability will get worse. The obtained results may be instructive for the purification and control of C impurity and the understanding of the formation mechanism of C containing gas in LaNi5 alloys.