Effect of Cr on ZrO2/Ni thermal barrier coatings interface cohesion
-
摘要: 热障涂层广泛用于航空、航天领域,涂层与基体的界面结合强弱是决定涂层寿命的一个关键因素.为了提高其使用寿命,必须要求涂层与基体的界面有较好的结合.利用密度泛函理论框架下的第一性原理离散变分(DV)方法研究了ZrO2Ni热障涂层界面的能量学和电子结构,讨论了替位型掺杂的Cr在ZrO2Ni热障涂层界面中的作用.结果表明:Cr容易偏聚于界面处(偏聚能达6.03eV),Cr使得体系结合能增加,体系更稳定,有利于界面的结合;界面处原子电荷占据数和电荷密度计算表明:加入Cr后跨界面方向的电荷密度增加,同时也使得界面内电荷密度增加,这有利于跨界面方向的以及沿界面方向的成键,从而加强了涂层与基体材料的结合.Abstract: The thermal barrier coatings (TBC) are widely used in aeronautics and astronautics industry. The cohesion between the coatings and substrate is a vital effect in determining the TBC lifetime. The interface cohesion must strong enough in order to have longer lifetime. Based on density functional theory the first-principles discrete variational (DV) method was used to study the thermal barrier coating. The energy and electronic structure of the Cr-doped interface of TBCs (ZrO2Ni) were investigated. Result shows that after adding Cr on the interface, the system’s energy is reduced. The segregation energy of Cr is 6.03 eV. This means the system is more stable when Cr atom segregates on interface than that of clean system. Further analysis shows that the interface’s charge-density is increased after adding Cr, this is propitious to bond on the direction of spanning the interface, thereby the bonds between the substrate Ni and ZrO2 are enhanced; the bonds between atoms neighboring to Cr atom in plane are also enhanced.
-
Key words:
- heat barrier coats /
- charge density /
- first-principles /
- interface cohesion
-
[1] Xu Huibin, Guo Hongbo, Liu Fushun, et al. Development of gradient thermal barrier coatings by EB-PVD and their hot-fatigue behaviors [J]. Surface & Coating Technolgy, 2000, 130:133~139 [2]Guo Hongbo, Bi Xiaofang, Gong Shengkai, et al. Microstructure investigation on gradient porous thermal barrier coatings prepared by EB-PVD[J].Scripta Materialia, 2001, 44:683~687 [3]Guenzburger D, Ellis D E. Magnetism of Fe impurities in alkaline-earth metals and Al[J].Physical Review B, 1992, 45:285~294 [4]Ellis D E, Benesh G A, Byrom E. Molecular cluster studies of binary alloys:LiAl [J]. Physical Review B, 1977, 16:3308~3313 [5]Delley B, Ellis D E. Efficient and accurate expansion methods for molecules in local density models [J]. Journal Chemical Physics, 1982, 76:1949~1960 [6]Delley B, Ellis D E, Freeman A J, et al. Binding energy and electronic structure of small copper particles [J]. Physical Review B, 1983, 27:2132~2144 [7]Barth U V, Hedin L. A local exchange-correlation potential for the spin polarized case:I [J]. Journal Physics C, 1972, 5:1629~1642 [8]Shang Jiaxiang, Zhao Dongliang, Wang Chongyu. The preferred-site tendency of alloying element Nb in Fe γ phase and its effect on grain boundary cohesion[J]. Science in China, Series E,2002,45(1):90~96 [9]Ellis D E, Painter G S. Discrete variational method for the energy-band problem with general crystal potentials[J]. Physical Review B, 1970, 2:2887~2898 [10] Shang Jiaxiang, Wang Chongyu, Zhao Dongliang. First-principles investigation of the effect of alloying elements Ti, V on grain boundary cohesion of FCC Fe [J]. Computational Materials Science, 2001, 22:193~199 [11]Shang Jiaxiang, Wang Chongyu. First-principles investigation of brittle cleavage fracture of Fe grain boundary [J]. Physical Review B, 2002,66:184105-1~184105-10 [12]Shang Jiaxiang, Wang Chongyu. Electronic effects of alloying elements Nb and V on boday-centred-cubic Fe grain boundary cohesion [J]. Journal Physics:Condensed Matter, 2001, 13:9635~9644 [13]Wang Fuhe, Wang Chongyu, Yang Jinlong. The effect of boron on the electronic structure of grain boundaries in Ni3Al [J]. Journal Physics:Condensed. Matter, 1996, 8:5527~5534 [14]Wang Fuhe, Wang Chongyu. First-principles investigation of hydrogen embrittlement in polycrystalline Ni3Al [J]. Physical Review B, 1998, 57:289~295 [15]Wang Fuhe, Wang Chongyu. The effect of Zirconium on the electronic structure of grain boundaries in Ni3Al [J]. Journal Physics:Condensed Matter, 1997, 9:4499~4507 [16]Wang Fuhe, Shang Jiaxiang, Li Jiaming, et al. The effect of boron and hydrogen on the embrittlement in polycrystalline Ni3Al [J]. Intermetallics, 2000, 8:589~593
点击查看大图
计量
- 文章访问数: 2866
- HTML全文浏览量: 141
- PDF下载量: 3
- 被引次数: 0