Calculation And Research On Rare Earth Elements Doped AgSnO₂ Contact Materials

Excellent and green AgSnO₂ contact materials are most likely to replace toxic AgCdO.The electrical conductivity of Ag and the thermal stability of SnO₂ make AgSnO₂ have arc erosion resistance,wear resistance and welding resistance.However,the SnO₂ is a semiconductor with wide band gap.Under the action of the arc,the SnO₂ with high decomposition temperature and non-conductivity is easy to enrich on the surface of the contact materials,so that the contact resistance will increase and the electrical life will shorten.Therefore,it is significant to find appropriate elements doping SnO₂ to improve the electrical properties of AgSnO₂.The traditionally experimental study of doping chooses elements and technology only by trial and error method,and it wastes manpower,physical and financial resource.So researching the influence of doping elements on the electrical conductivity of SnO₂ from microscopic mechanism on the first,then verifying and complementing theoretical results through the experiment is also significant,which is a good research ideal that choose the theory to guide the experiment and make the theory combine with the experiment.This paper used CASTEP software to calculate rare earth elements?La,Ce,Nd,Sm,Gd?doped SnO₂ by first-principles.By contrasting band structure and density of states of pure SnO₂ and doped SnO₂,the effect of rare earth elements doping on the electrical conductivity of SnO₂ was analyzed theoretically.Under the guidance of theoretical analysis,experiments were carried out.Firstly,pure SnO₂ and doped SnO₂ powders were prepared by sol-gel method,and the agreement between the powder structure and the theoretical calculation model was verified by XRD experiment.Then pure AgSnO₂ and doped AgSnO₂ were fabricated by powder metallurgy process.Through testing the physical properties and conducting electrical contact experiments,the theoretical results were verified and supplemented.