| Rare earth-based oxides have the advantages of high thermal stability,cycle availability,and environmental friendliness,and are widely used in the field of coatings and solid batteries.The rare earth-based oxide doped with zirconia has excellent thermal stability,thermal shock resistance and sintering resistance,and the prepared rare earth-based zirconate can be used as a thermal barrier coating material.The cerium oxide-based solid fuel cell doped with rare earth elements will undergo a phase transition in a high-temperature environment and during charging and discharging.At present,few studies have pointed out the phase change of the material during use.In this paper,the solid phase sintering method was used to prepare Ce O2-Re2O3?Re=Sm,Eu,Gd?binary system and Ce O2-Eu2O3-Zr O2 ternary system samples,using scanning electron microscope?SEM?,X-ray diffractometer?XRD?and Electronic probe?EPMA?method was used to determine the phase diagram of binary system and the equilibrium relationship of ternary system at 1400?.The main research results obtained by the paper are as follows:?1?In this work,a self-consistent phase diagram of the binary system Ce O2-Re2O3?Re=Sm,Eu,Gd?has been obtained.The Ce O2-Re2O3?Re=Sm,Eu,Gd?binary system contains three single phases,namely monoclinic B-Re2O3 phase,cubic C-Re2O3 phase and cubic F-Ce O2 phase.Containing two dual-phase regions were B-Re2O3 and cubic C-Re2O3 phase regions,cubic C-Re2O3 and cubic F-Ce O2 phase regions.?2?In Ce O2-Re2O3?Re=Sm,Eu,Gd?system,two factors control the lattice will reduce the volume of electrons,and the size of phase B is controlled by the smaller solid solubility;For another,the introduction of oxygen vacancies outside the gap will cause repulsion between ions and increase the electronic parameters,resulting in F-type The solid solubility in the crystal is large.?3?Doped with rare erath elements in cerium oxide and increases as the atomic number?Sm-Gd?,the content of B-phase solid solution cerium oxide gradually decreases.Ceria is also an important factor for stabilizing the B+C phase.As the atomic number increases,the B+C two-phase region gradually narrowed.?4?The phase relationship of Eu2O3-Ce O2-Zr O2 at 1400?was determined.At this temperature,there are six phase were identifiedin system:Zr O2?T?,Ce O2?F?,Eu2O3?B,C?,Eu2Zr2O7?Py?and the solid solution?F?formed by Zr O2 and Eu2O3.The Eu2O3-Ce O2-Zr O2 1400?isothermal cross section was constructed,which includ five two-phase regions:B+C,C+F,F+Py,F+T,and F+T. |
PDF Full Text Request