摘要
为了研究涂层中Ti/TiB _2界面性质,本文采用第一性原理方法计算了Ti(0001)和TiB _2(0001)的表面能,6种不同Ti(0001)/TiB _2(0001)界面的黏附功和界面能,并且分析了它们的电子密度、差分电荷密度和分波态密度(PDOS).研究结果表明,当TiB _2(0001)表面的原子层数n≥9时,其表面深处的原子具有体相原子的特征.在6种不同的界面中,B终端的Ti/TiB_2界面稳定性均优于Ti终端的界面,且B终端的孔穴位堆垛界面(BTH)和Ti终端的心位堆垛界面(TTC)分别是两种终端最稳定的界面.此外,BTH界面具有最大的黏附功(7.72 J/m^2),它在整个Ti元素的化学势(-3.2~0 eV)范围内也具有最低的界面能,说明BTH界面具有最好的稳定性和结合强度.电子性质和PDOS的研究结果表明,BTH界面主要由Ti–B共价键和Ti–Ti金属键构成,且Ti–B共价键是主要由界面处的B 2p和Ti3d轨道杂化所形成的.
The adhesion strength between Ti and TiB2, commonly employed in wear-resistant and oxidation-resistant coatings, depends on their interfacial properties. However, it is difficult to clearly understand the interaction of the Ti/TiB2 interface at the atomic or even electronic scale through experimental methods. Therefore, the first-principles calculation has been employed to study the Ti/TiB2 interface in this article. First of all, properties of the Ti（0001） surface, TiB2（0001） surface, and Ti（00011）/TiB2（0001） interfaces were investigated by first-principles calculations based on density functional theory （DFT）. Considering two termination and three possible sequences, six interface models were studied in this work. Additionally, the work of adhesion （Wad）, interface energy （γint）, and electronic structure of these interfaces were calculated. The results show that the calculated bulk properties of Ti and TiB2 are in good agreement with the experimental data and the values of other studies, indicating that the parameters used in our calculations are reliable. For the TiB2（0001）, the B-terminated surface is less stable than the C-terminated one at low △μTi The surface energy of the B-terminated surface decreases with increasing △μTi, whereas the energy of the Ti-terminated surface increases. Consequently, the B-terminated surface is more stable when △μTi〉-1.27 eV/unit cell. The calculated Wad results indicate that both of Wad and interfacial separation （do） are affected by the termination and stacking sequences. The Wad of the Ti/TiB2 interfaces with B termination is larger than that of the ones with Ti termination, which suggests that the stability and adhesion strength of the former are better than that of the latter. For the Ti/TiB2 interfaces with the same termination, the B-terminated hollow-stacked （BTH） interface and Ti-terminated hollow-stacked （TTC） interface are considered as the optimal ones. For the B-terminated interfaces, the Wad of the interfac
作者
熊辉辉
姜平国
都政
陈聪梅
XIONG HuiHui JIANG PingGuo DU Zheng CHEN CongMei(School of Metallurgy and Chemical Engineering, Jiangxi University of Science and Technology, Ganzhou 341000, China National Supercomputing Center in Shenzhen （Shenzhen Cloud Computing Center）, Shenzhen 518055, China)
出处
《科学通报》
EI
CAS
CSCD
北大核心
2017年第15期1655-1661,共7页
Chinese Science Bulletin
基金
国家自然科学基金(51564016
51404113)资助
关键词
Ti/TiB2界面
黏附功
界面能
第一性原理
Ti/TiB2 interface, work of adhesion, interfacial energy, first principles
