First principle calculation of the binding mechanism between Ti and SiO2
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摘要: Ti元素是钎焊SiO2f/SiO2复合材料重要的活性元素，因此，使用第一性原理计算研究了Ti和SiO2的界面结合机制. 分别建立了两种不同的终止面和化学计量比的界面，使用界面分离功、电子行为和界面能研究了界面原子间的结合. 结果表明，在O终止界面中，界面处Ti和O形成很强的离子-共价键，界面分离功最大可达到8.99 J/m2. 在Si终止面界面中，Ti和Si形成共价-离子键，界面分离功为2.65 J/m2. 在温度为1 173 K时，当Si的活度大于e−35时，富Si界面的界面能更低，界面倾向于形成Ti-Si化合物. 当Si的活度小于e−35时，富O界面在热力学上更加稳定，界面倾向于形成Ti-O化合物. SiO2中的Si被Ti置换出后，Si扩散进入钎料，活度升高，与钎料中的Ti反应生成Ti-Si化合物，所以界面结构为SiO2/Ti-O化合物/Ti-Si化合物/钎料.Abstract: Ti is an important active element to join SiO2f/SiO2 composite materials. Therefore, the bonding mechanism of Ti and SiO2 was studied by using first principle calculation. Two kinds of interfaces with different termination and stoichiometric ratio were studied by the results of work of separation (Wsep), electron behavior and interface energy. It is found that in the O-terminated interface, Ti and O atoms form a strong ionic-covalent bonding, resulting in the largest Wsep of 8.99 J/m2. In the Si-terminated interface, Ti and Si atoms form covalent-ionic bonding, and the Wsep is 2.65 J/m2. At the temperature of 1 173 K, when the activity of Si is larger than e−35, the interface of Si-terminated interface is more lower. The Ti-Si compounds are more favored at the interface. When the activity of Si is smaller than e−35, the O-terminated interface is more stable in thermodynamics and the Ti-O compounds are more favored at the interface. After Si in SiO2 in replaced by Ti, Si will diffuse into the solder and react with Ti in the solder to form Ti-Si compounds, so the interface struture is SiO2/Ti-O compound/Ti-Si compound/solder.
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图 1 Ti/SiO2界面结构侧视图和三种不同界面结构俯视图
Figure 1. Side view of Ti/SiO2 interfacial structure and three interface configurations. (a) O termination surface；(b) Si termination surface；(c) top；(d) bridge； (e) hollow
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图 3 驰豫后的Ti/SiO2界面结构侧视图
Figure 3. Side view of relaxed Ti/SiO2 interfacial structure. (a) O termination surface; (b) Si termination surface
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图 4 驰豫后界面的差分电荷密度图
Figure 4. Charge density difference for the interface after relaxation. (a) O termination surface; (b) Si termination surface
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图 5 驰豫后界面特定原子的PDOS
Figure 5. PDOS projected on selected atoms of interface after relaxation. (a) O termination surface; (b) Si termination surface
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[1] Sun Z, Zhang L X, Qi J L, et al. Brazing of SiO2f/SiO2 composite modified with few-layer graphene and Invar using AgCuTi alloy[J]. Materials & Design, 2015, 88: 51 − 57.
[2] Lin J H, Luo D L, Chen S L, et al. Control interfacial microstructure and improve mechanical properties of TC4-SiO2f/SiO2 joint by AgCuTi with Cu foam as interlayer[J]. Ceramics International, 2016, 42(15): 16619 − 16625. doi: 10.1016/j.ceramint.2016.07.084
[3] Liu X, Huang X M, Ma H B, et al. Microstructure and properties of the joints of ZrO2 ceramic/stainless steel brazed in vacuum with AgCuTi active filler metal[J]. China Welding, 2018, 27(02): 52 − 56.
[4] Xin C, Yan J, Xin C, et al. Effects of Ti content on the wetting behavior and chemical reaction in AgCuTi/SiO2 system[J]. Vacuum, 2019, 167: 152 − 158. doi: 10.1016/j.vacuum.2019.05.014
[5] Zhang L X, Wu L Z, Liu D, et al. Interface microstructure and mechanical properties of the brazed SiO2 glass ceramic and 30Cr3 high-tensile steel joint[J]. Materials Science & Engineering: A, 2008, 496(1-2): 393 − 398.
[6] 林景煌, 霸金, 亓钧雷, 等. SiO2f/SiO2复合材料表面碳活化辅助钎料润湿机理[J]. 焊接学报, 2017, 38(5): 83 − 86. Lin Jinghuang, Ba Jin, Qi Junlei, et al. Wetting mechanism of carbon activated auxiliary solder on the surface of SiO2f/SiO2 composite[J]. Transactions of the China Welding Institution, 2017, 38(5): 83 − 86.
[7] Li J, Yang Y, Li L, et al. Interfacial properties and electronic structure of β-SiC(111)/α-Ti(0001): A first principle study[J]. Journal of Applied Physics, 2013, 113(2): 55 − 60.
[8] Du J L, Fang Y, Fu E G, et al. What determines the interfacial configuration of Nb/Al2O3 and Nb/MgO interface[J]. Scientific Reports, 2016, 6: 33931. doi: 10.1038/srep33931
[9] Shi S, Tanaka S, Kohyama M. First-principles study of the tensile strength and failure of alpha-Al2O3(0001)/Ni(111) interfaces[J]. Phyical Review B, 2007, 76(7): 075431. doi: 10.1103/PhysRevB.76.075431
[10] Yang L T, Jiang Y, Wu Y, et al. The ferrite/oxide interface and helium management in nano-structured ferritic alloys from the first principles[J]. Acta Materialia, 2016, 103: 474 − 482. doi: 10.1016/j.actamat.2015.10.031
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