气体在玻璃中渗透的数值模拟  

Numerical Simulation of Gas Permeation in Glass

作　　者：程宏昌 程耀进 庞妍 胡文波[2] 卜忍安[2] 樊慧庆[3] CHENG Hongchang;CHENG Yaojin;PANG Yan;HU Wenbo;BU Ren'an;FAN Huiqing(Science and Technology on Low-Light-Level Night Vision Laboratory&Kunming Insttute of Physics,Kunming 650223,China;Key Laboratory for Physical Electronics and Devices of the Ministry of Education,Xi'an Jiaotong Universty,Xi'an 710049,China;School of Materials Science and Engineering&Northwestern Polytechnical Universty,Xi'an 710072,China)

机构地区：[1]昆明物理研究所微光夜视技术重点实验室,昆明650223 [2]西安交通大学电子物理与器件教育部重点实验室,西安710049 [3]西北工业大学材料学院,西安710072

出　　处：《西安交通大学学报》2020年第1期1-7,共7页Journal of Xi'an Jiaotong University

基　　金：微光夜视技术重点实验室基金资助项目(614241204021703,20160103,20150103)

摘　　要：为深入理解环境气体对超高真空电子器件玻璃壳体材料的渗透机理,采用巨正则蒙特卡罗法和分子动力学法对玻璃中的气体溶解、扩散两种渗透行为进行了数值模拟研究,基于原子模拟凝聚相优化分子势力场,计算了两种玻璃结构中氧气、氦气、氢气和水蒸气分子的溶解系数,以及氧气和氢气分子在钠钙玻璃中的扩散、渗透系数和扩散运动轨迹。计算结果表明:与玻璃材料亲和力较大的气体分子溶解系数较高;玻璃中金属离子的存在使玻璃中的孔径变小,从而降低了钠钙玻璃中气体分子的溶解系数;环境温度升高和气体压强增加使气体分子在玻璃中的扩散、渗透系数增加;在扩散过程的大部分时间中,气体分子在某一位置做往复振动,偶尔发生一次跳跃,这导致气体分子逐渐远离初始位置;因为玻璃材料能给体积较小的气体分子提供更多的有效扩散通道,所以H2比O2有较高的扩散系数。研究结果可为超高真空电子器件的真空失效机制探究、玻璃壳体的材料优选和结构优化提供一定的理论依据。To understand the penetration mechanism of ambient gases in glass shell materials of ultra-high vacuum electronic devices in depth,numerical simulation of gas permeation including dissolution and diffusion processes in glass was studied with the methods of giant canonical Monte Carlo and molecular dynamics.The solubility coefficients of oxygen,helium,hydrogen and water vapor molecules in two kinds of glass structure,together with the diffusion coefficients,permeability coefficients and motion trajectories of oxygen and hydrogen molecules in soda-lime glass,were calculated based on the COMPASS(Condensed-phase optimized molecular potentials for atomistic simulation studies)force field.The calculation results show that a kind of gas having a higher affinity with glass has a higher solubility coefficient.Metal ions distributed in glass make the size of pores in glass smaller,which results in a lower gas solubility coefficient of soda-lime glass.Both of rising environment temperature and gas pressure can push up the diffusion and permeability coefficients of gases.During the diffusion process,most of the time gas molecules vibrate in certain positions and occasionally jump once,which makes gas molecules gradually apart from their initial positions.H2 molecules have a higher diffusion coefficient compared with larger O2 molecules because glass can provide more effective diffusion channels for gas molecules with smaller size.The research results can provide theoretical bases for exploring the vacuum failure mechanism of ultra-high vacuum electronic devices and optimizing the material and structure of glass shells used in devices.

关 键 词：玻璃结构 气体渗透 溶解扩散 数值模拟 

分 类 号：TB71[一般工业技术—真空技术]