Study On Preparation Of The YSZ-TZP Electrolyte Thin Substrate By Gelcasting Technology And Its Properties

In this paper, the preparation process and the properties of YSZ-TZP solid electrolyteby the gelcasting technology were studied. The phase composition of material andmicrostructure were investigated by XRD,SEM and so oa The mechanical andelectrical properties of the electrolyte material were also studied.The stability and fluidity properties of YSZ-TZP suspensions were studied firstly andthe effect of some parameters such as pH value, dispersant content on the stability andfluidity properties of the suspensions were determined. The isoelectric point (EEP) of YSZis about 6.8, and for TZP the IEP is about 8.8.The dispersant (PAANH₄) can greatly affectthe surface chemical properties of both YSZ and TZP, and it can also change theisoelectric points of the two powders to about 2. The suspension is stable in the alkali pHrange, especially in the range of 8-10. The viscosities of slurries decrease and thenincrease with the increment of dispersant and an optimum content of dispersant exists foreach. The volume solid loading can reach 50%. The optimum pH range is 8-10;dispersant content is 0.1wt%-0.2wt%. The electrolyte substrates is lower than 1mm whichcan be sintered at 1600℃ were fabricated.The gellation process of slurry was studied. Acrylamide system and heating gellation were adopted. The formed green thin substrate is smooth and flexible with a certain strength and uniform microstructure.The densification process was investigated. The density of YSZ increases with the increment of sintering temperature. TZP can increase the density and shrinking rate of material and decrease sintering temperature. YSZ is cubic phase, as for YSZ-TZP is cubic and tetragonal phase .The monothic zirconia exists in green bodies, but not found in the sintered materials. The grain of YSZ is mainly homogeneous hexagon, the pores are mainly appears in grain boundaries. With increasing TZP content, the grains deviate from homogeneous hexagon, some small grains are observed in sintered bodies. The pores situate at the internal part of grains and grain boundaries, mainly in the internal part of...