La掺杂AgSnO2触头材料的电性能

由于Cd有毒性,AgSnO2触头材料逐渐取代了 AgCdO 成为新型触头材料,但由于AgSnO2触头材料中的SnO2近乎绝缘,使得触头材料的接触电阻增大,故改善SnO2的导电性是急需解决的重大难题.本文提出了一种简单的、低成本的La掺杂AgSnO2触头材料的设计方法.采用模拟计算的方法,利用第一性原理的密度泛函理论平面波超软赝势法,建立了SnO2以及不同比例La掺杂的SnO2超晶胞模型,在对其进行几何优化之后分别研究了 La掺杂比为50%、25%、16. 67%、12. 5%、8.34% 的SnO2材料的电子结构,并研究了其晶格参数、能带结构和态密度等.结果表明,掺杂后材料晶胞体积变大. La的5d轨道进入导带,使得导带底向低能端移动,禁带宽度变小.最终得出La掺杂比为16.67% 时导电性最佳.最后进行了不同掺杂比下触头材料的电接触性能试验,得到了接触电阻和燃弧能量等电接触性能参数并验证了模拟结果.因此,本文的研究为触头材料的发展和应用提供了理论依据.

Electrical Properties of La Doped AgSnO2 Contact Materials

Due to toxicity of Cd ,AgCdO contact material is gradually replaced by AgSnO2,a new type of contact material .Because SnO2is almost insulated addition of SnO2 makes the resistance of this material increase ,to improve the electrical conductivity of thematerial is thus a major problem to be solved .A simple and low cost method for the design of La doped AgSnO2 contact material is reported .The electronic structures of La doped SnO2 with different proportions (50%,12.5%, 16.67%,8.34%,25%) were calculated by the first principle calculation method based on density functional theory .The lattice parameters ,band structure and density of states were analyzed .Some results show that the cells are larger after doping ,and the 5d orbit of La moves to the conduction band ,which leads to a movement of the conduction band bottom towards lower energy zone and the narrowing of the band gap .In conclusion ,when the doping ratio is 16.67%,the conductivity is the best .Measurements of contact resistance and arc energy of the contact material with different doping ratios were also carried out to verify the simulation results .Therefore ,a theoretical basis for the development and application of contact materials is provided .