Pb((Zn1/3Nb2/3)0.16(Fe1/2Nb1/2)0.48(Fe2/3W1/3)0.36)O3 and Pb((Fe1/2Nb1/2)0.7(Fe2/3W1/3)0.3)O3 ceramics prepared by simplifiedwolframite route
碩士 === 崑山科技大學 === 電子工程研究所 === 93 === Pb((Zn1/3Nb2/3)0.16(Fe1/2Nb1/2)0.48(Fe2/3W1/3)0.36)O3 (PZFNW) perovskite ceramics produced by a simplified wolframite route were investigated. The mixture of ZnO, Fe2O3, Nb2O5 and WO3 was calcined to form B-site precursor then mixed with PbO. The mixed powder was...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2005
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| Online Access: | http://ndltd.ncl.edu.tw/handle/zuf99a |
| Summary: | 碩士 === 崑山科技大學 === 電子工程研究所 === 93 === Pb((Zn1/3Nb2/3)0.16(Fe1/2Nb1/2)0.48(Fe2/3W1/3)0.36)O3 (PZFNW) perovskite ceramics produced by a simplified wolframite route were investigated. The mixture of ZnO, Fe2O3, Nb2O5 and WO3 was calcined to form B-site precursor then mixed with PbO. The mixed powder was pressed and sintered to form PZFNW ceramics without the second calcination of wolframite route involved. Pyrochlore-free PZFNW ceramics were obtained by simplified wolframite route after sintered at temperatures from 850oC to 930oC for 2 h to 6 h. Density increases with sintering temperature and a maximum value 8.24g/cm3 (94.7% of theoretical value) was obtained at 930oC for 4 h. Grain sizes of 1.87-8.63μm were formed by heating rate 5℃/min at 850-930oC, 1.78-5.85μm by heating rate 10℃/min at 850-930oC and 1.25-5.25μm by heating rate 15℃/min at 850-930oC. Dielectric constant at room temperature reaches 15500 under 100kHz after sintered at 930oC for 4 h.
With the same method, we can prepare pyrochlore free Pb((Fe1/2Nb1/2)0.7(Fe2/3W1/3)0.3)O3(PFNW) perovskite ceramics after sintered at temperatures from 950oC to 1030oC for 2 h to 6 h. Density increases with sintering temperature and a maximum value 8.55g/cm3 (98% of theoretical value) was obtained at 1000oC for 6 h. Grain sizes of 3.54-8.8μm were formed by heating rate 5℃/min at 950-1030oC, 3.45-8.57μm by heating rate 10℃/min at 950-1030oC and 2.18-7.52μm by heating rate 15℃/min at 950-1030oC. Dielectric constant at room temperature reaches 29000 under 100kHz after sintered at 1000oC for 6 h.
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