Preparation and Characterization of Pb,Ni,Cu or Ag doped Lanthanum Indium Gallium Oxides

• Main Authors: Yuan-JenHsieh, 謝沅任
• Other Authors: Chen-Feng Kao
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/25045625877934805705

碩士 === 國立成功大學 === 化學工程學系碩博士班 === 98 === Chemical coprecipitation has high homogeneity, high reactivity, high quality and exact stochiometry. The goal of this study is that the lanthanum-indium -gallium oxide powders Pb,Ni,Cu or Ag doped were prepared by coprecipitation method. The synthesis, characterization and electrical properties of the above compounds were investigated. The precursors of lanthanum-indium- gallium oxide with OH- ligands were prepared by coprecipitation. After freeze drying, the precursors were calcined at 900,1000 and 1100 ℃ for 2 h to obtain the corresponding compounds without Pb,Ni,Cu or Ag doped respectively. It indicated from XRD patterns that the major compounds were lanthanum-indium-gallium oxide.Pb,Ni,Cu or Ag doped lanthanum-indium- gallium oxide indicated from XRD patterns that the major compounds had not other phase presently. Calcined powders were pressed into disks and then were sintered for 8h at 1200 ℃、1300 ℃、1400 ℃. From XRD patterns, it revealed that they formed solid solution systems of LaInO3-LaGaO3. High resistance meter was used to measure the D.C. resistance of the samples. It was found that the resistance of the lanthanum-indium- gallium oxides are 1010 Ω-cm which sintered at 1400 oC, 107 Ω-cm which sintered at 1300 oC,and 106 Ω-cm which sintered at 1200 oC.When Pb,Ni,Cu or Ag doped lanthanum-indium- gallium oxide,the resistance decreases with increasing ratio of doping.The D.C. resistance of the sample with Pb doped is 2.41~7.07×106 Ω-cm,with Ni doped is 2.11~4.66×106 Ω-cm,with Cu doped is 1.48~3.10×106 Ω-cm,and with Ag doped is 1.09~1.32×106 Ω-cm. LCR meter was used to measure the electrical capacity of the samples. Dielectric constants were calculated from the electrical capacity via the formula. It was found that lanthanum-indium- gallium oxides has low dielectric constants. The dielectric constant of lanthanum-indium- gallium oxide sintered at 1400 oC is 13~14, sintered at 1300 oC is 14~17,and sintered at 1400 oC is 17~25.The dielectric constant decreases with increasing sintering temperature and frequency, measured by the LCR.And the dielectric constant increase with increasing doping ratio and element. The dielectric constant of the sample with Pb doped is 22~31,with Ni doped is 35~49,with Cu doped is 47~51,and with Ag doped is 59~67.