The Preparation And Properties Of Ce_xZr_1-xO₂ And （YSZ）_1-x（Fe₂O₃）_x

Ce_xZr_1-xO₂ was synthesized by low-temperature solid-solid reaction method.The phase structure,micro-morphology,thermal expansion properties,thermal shock resistance,total conductivity and electronic conductivity of Ce_xZr_1-xO₂ were characterized by XRD,SEM,thermal expansion instrument,thermal shock instrument,DC Van Der Pauw method and DC polarization method（Hebb-Wagner）,respectively.The effects of CeO2 doping on properties of Ce_xZr_1-xO₂ solid solution were investigated.The XRD results indicate that the Ce0.25Zr0.75O2 powder is t-ZrO2,while the Ce0.75Zr0.25O2 powder is c-CeO2.The EDS results show that the molar ratios of Ce to Zr are consistent with the stoichiometric ratio of Ce_xZr_1-xO₂.The coefficient of linear expansion of Ce_xZr_1-xO₂ is in 13.27×10-6～-14.72×10-6·K-1 at temperature range from ambient temperature to 1400 ℃.The thermal shock resistance of Ce_xZr_1-xO₂ is poor.The total conductivity and electronic conductivity of Ceo.75Zro.25O2 are maximum,reaching to 1.02x10-2 S·cm-1 and 1.02×10-4 S·cm-1,respectively,while the total conductivity and electronic conductivity of Ce0.25Zr0.75O2 are minimum,reaching to 2.72×10-4 S·cm-1 and 4.96x10-6 S·cm-1,respectively,at 850 ℃.The（4.167YSZ）_1-x（Fe₂O₃）x and（9YSZ）_1-x（Fe₂O₃）solid solution materials were synthesized by chemical coprecipitation method.The phase structure,thermal shock resistance,total conductivity and electronic conductivity of（YSZ）_1-x（Fe₂O₃）x were characterized by XRD,thermal shock instrument,DC Van Der Pauw method and DC polarization method（Hebb-Wagner）,respectively.The effects of Fe₂O₃ doping on properties of（YSZ）_1-x（Fe₂O₃）x solid solution were investigated.The XRD results indicated that the solubility of Fe₂O₃ in 4.167YSZ is in 7.82～9.03mol%,while the solubility of Fe₂O₃ in 9YSZ is in 6～7.82mol%.The XRD results also show that the（4.167YSZ）_1-x（Fe₂O₃）x（x=0,0.0105,0.0433,0.0782）powders are c-ZrO2 and t-ZrO2,while（9YSZ）_1-x（Fe₂O₃）x（x=0,0.0105,0.0433,0.06）powders are c-ZrO2.The thermal shock resistance of（YSZ）_1-x（Fe₂O₃）x is excellent and the loop count is more than 30 times.In air atmosphere,the conductivity of（9YSZ）]1-x（Fe₂O₃）x are higher than that of（4.167YSZ）_1-x（Fe₂O₃）x.For example,the total conductivity and electronic conductivity of（9YSZ）0.9895（Fe₂O₃）0.0105 are maximum in（9YSZ）_1-x（Fe₂O₃）x,the values of which are 1.72×10-2 S·cm-1 and 6.30×10-3 S·cm-1 at 750 ℃,respectively.The total conductivity and electronic conductivity of（4.167YSZ）0.9567（Fe₂O₃）0 0433 are maximum in（4.167YSZ）_1-x（Fe₂O₃）x,the values of which are 5.78×10-3 S·cm-1 and 4.19×10-4 S·cm-1 at 750 ℃,respectively.