Preparation and Sintering of Perovskite-Type Compound Powders by the Hydrazine Method

肼法钙钛矿型复合粉体的制备与烧结

• 批准号: 06650969
• 负责人: HIROTA Ken
• 金额: $ 1.34万
• 依托单位: Doshisha University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06650969/
• 关键词: Hydrazine; Perovskite; Lanthanum chromite; Lead zirconate; Lanthanum magnesium chromite; クロシア; クロミア; ランタンクロメイト

Submicron powders consisting of various kinds of perovskite-type compounds (PbZrO_3, LaCrO_3, LaCr_<0.85>Mg_<0.15-x>Co_xO_3 (x=0,0.05,0.10) have been prepared by the hydrazine method. Characterization of powders have been performed using transmission electron microscopy, differential thermal analysis, thermal gravimetry, X-ray diffraction analysis, and BET method. LaCr_<0.85>Mg_<0.15-x>Co_xO_3 powders have been sintered. Electrical and thermal properties of the sintered ceramics have been evaluated.1) PbZrO_3 Metastable ZrO_2 solid solutions containing up to 50 mol% PbO are formed at low temperatures from as-prepared amorphous materials ; the tetragonal phase up to 30 mol% PbO and the cubic phase between 30 and 50 mol% PbO.The compound PbZrO_3 is formed at 615ﾟ to 690ﾟC by transformation of c-ZrO_2 solid solution.2) LaCrO<@D23@>D2 Metastable LaCrO<@D24@>D2 crystallizes at (]SYgtoreq[)530ﾟC from as-prepared materials. The compound LaCrO<@D23@>D2 consisting of submicron powders (0.2mum) … More is formed at 840ﾟC by transformation of LaCrO<@D24@>D2.3) LaCr<@D20.85@>D2Mg<@D20.15-x@>D2Co<@D2x@>D2O<@D23@>D2 (x=0,0.05,0.10) As the same result as LaCrO<@D23@>D2, metastable LaCrO<@D24@>D2 solid solutions crystallize at low temperatures ((]SYapprxeq[)480ﾟC) from as-prepared amorphous materials. LaCrO<@D24@>D2 solid solutions transform at(]SYapprxeq[)780ﾟC into the compounds LaCr<@D20.85@>D2Mg<@D20.15-x@>D2Co<@D2x@>D2O<@D23@>D2 (x=0,0.05,0.10) consisting of submicron powders ((]SYapprxeq[)0.12mum). After being calcined at 1000ﾟC for 1h, the powders compacted into pellets at 343 MPa have been sintered at 1600ﾟC for 2h. Well-densified compacts ((]SYapprxeq[) 95% of theoretical) can be obtained, although these compounds show poor sinterability. The LaCr<@D20.85@>D2Mg<@D20.15-x@>D2Co<@D2x@>D2O<@D23@>D2 ceramics obtained show high electric conductivity of (]SYapprxeq[)8.8S・cm<@D1-1@>D1 at 1000ﾟC ; this value is about ten times higher than that of LaCrO<@D23@>D2 ceramics reported. Thermal expansion coefficients of ceramics alpha are (]SYapprxeq[)11.3-12.0x10<@D1-6@>D1K<@D1-1@>D1 in the temperature range between room temperature and 1000ﾟC ; the values are the same as c-ZrO<@D22@>D2. These results reveal that the LaCr<@D20.85@>D2Mg<@D20.15-x@>D2Co<@D2x@>D2O<@D23@>D2 ceramics are suitable candidates for electrodes in solid oxide fuel cell (SOFC) composed of c-ZrO<@D22@>D2 as a solid electroloyte. Less

用肼法制备了各种钙钛矿型化合物(PbZrO_3，LaCrO_3，LaCr_&lt；0.85&gt；Mg_&lt；0.15-x&gt；Co_xO_3(x=0，0.05，0.10))组成的亚微米粉末。用透射电子显微镜、差热分析、热重分析、X射线衍射分析和BET方法对粉末进行了表征。对LaCr0.85&gt；0.15-x&gt；CoxO_3粉末进行了烧结。1)非晶态材料在低温下形成PbO含量高达50%的PbO_2亚稳态固溶体，PbO含量在30~50摩尔%PbO之间形成四方相，立方相在30~50摩尔%PbO之间。化合物PbZrO_3是在615ﾟ~690ﾟC通过c-ZrO_2固溶体转变而形成的。2)Lacro&lt；@D23@&GT；D2亚稳态Lacro&lt；@D24@&GT；D2在()SYgtoreq[)530ﾟ℃结晶。由(0.2um)…亚微米粉末组成的化合物Lacro&lt；@D23@&Gt；D2Lacro&lt；@D24@&gt；D2.3)LaCr&lt；@D20.85@&gt；D2Mg&lt；@D20.15-x@&gt；D2Co&lt；@D2x@&gt；D2O&lt；@D23@&gt；D2(x=0，0.05，0.10)在840ﾟ℃转变形成更多，与Lacro&lt；@D23@&gt；D2，亚稳Lacro&lt；@D24@&gt；D2固溶体由所制备的非晶态材料在低温(SYapprxeq[)480ﾟC)下结晶。LaCr&lt；@D20.85@&gt；D2Mg&lt；@D20.15-x@&gt；D2Co&lt；@D2x@&gt；D2O&lt；@D23@&gt；D2(x=0，0.05，0.10)由亚微粉(SYapprxeq[)0.12um)组成的化合物ﾟ(x=0，0.05，0.10)。在1000ﾟC下焙烧1h后，在343 Mpa下压制成球团，然后在1600ﾟC下烧结2小时。虽然这些化合物的烧结性较差，但可以获得致密性良好的压坯(()SYapprxeq[)理论上的95%)。得到的LaCr&lt；@D20.85@&gt；D2Mg&lt；@D20.15-x@&gt；D2Co&lt；@D2x@&gt；D2O&lt；@D23@&gt；D2陶瓷在1000ﾟ℃下表现出()8.8s·cm&lt；@d1-1@&gt；d1的高电导率，这一值约为文献报道的Lacro&lt；@d23@&gt；d2陶瓷的10倍。α陶瓷的热膨胀系数在室温至1000ZrO℃之间的温度范围内为(]SYapprxeq[)11.3-12.0x10&lt；@D1-6@&gt；D1K&lt；@D1-1@&gt；D1，其值与c-ﾟ；@D22@&Gt；D2相同。这些结果表明，LaCr&lt；@D20.85@&gt；D2Mg&lt；@D20.15-x@&gt；D2Co&lt；@D2x@&gt；D2O&lt；@D23@&gt；D2陶瓷适合作为固体氧化物燃料电池的电极材料，由c-ZrO&lt；@d22@&gt；d2组成。较少

项目成果

K. Hirota et al.: "Formation of PbZrO_3 by Transformation of Cubic ZrO_2 Solid Solution" J. Am. Ceram. Soc.78. 3163-3164 (1995)

K. Hirota 等人：“通过立方 ZrO_2 固溶体的转化形成 PbZrO_3”J. Am。