The Effect Of Diffusion Diffusion Of Heterovalent Elements On The Conductance Behavior Of GDC Films Prepared By Magnetron Sputtering

Compared with the traditional oxygen ion conductor solid electrolyte YSZ,GDC has been widely studied because of its higher conductivity in intermediate-temperature condition.In order to meet the trend of the development of the electrolyte materials in the process of thin film and intermediate-temperature,it is more and more important to study the preparation technology and the electrical conductivity of GDC electrolyte.In this paper,GDC thin films were prepared on the single crystal Al2O3 substrates by reactive DC magnetron sputtering,The results of X-ray diffraction patterns phase analysis show that the GDC films prepared by magnetron sputtering have cubic fluorite structure,and the growth of(111)surface is preferred.The results of SEM morphology show that the GDC films have a typical columnar crystal structure,and the bonding force between the film and substrate is good and the results of TEM analysis show that the grain size of GDC thin film is between lOnm and 100nm at different annealing temperatures.The Sol containing Fe and Si elements were prepared by sol-gel method,the sol is coated on the surface of the film,and then the Fe element and Si element were doped into the grain boundaries by thermal diffusion process,the energy spectrum analysis shows that the grain boundary of the GDC thin film contains the silicon phase,and the doped Fe element can adsorb the silicon phase from the grain surface to the junction of the three grains.The conductivity of GDC thin films shows that the doping of Fe can improve the conductivity of the thin films,the conductivity has 7 times increased at 800 ?,The activation energy of the crystal did not vary,that is to say,the conduction mechanism does not change.When doped with Si element,the conductivity of the samples was tested and compared with those of the prepared and doped Fe elements,The conductivity of doped Si samples decreased significantly,while Fe doping can significantly improve the conductivity,this further indicates that the Fe doping clear grain boundary phase silica to improve the conductivity of GDC films.Through studying the relation between oxygen partial pressure and conductivity of GDC thin film,we can find that the oxygen partial pressure make contribution to the conductivity of GDC thin film.By controlling the annealing temperature,we tested the grain size of the samples at 25 ?,500?,800 ? and 1200 ? annealing temperature and microstructure,the electrical properties of their established relationships between grain size and conductivity,from the experimental results of 800 annealing temperature is best.