本實驗著力於以化學共沉法製備最佳比例之鑭銦鎵氧化物陶瓷粉末，並摻入不同比例的鉛、鎳、銅、銀等元素，探討此化合物的合成法式以及特性分析；此乃由於化學共沉法具有高均勻性、高反應性、高品質，以及精確的化學計量比。
以化學共沉法製得鑭銦鎵之前導化合物，經冷凍乾燥後，分別於900oC、1000 oC、 1100 oC煆燒2小時。將煆燒後之產物壓錠，於1200 oC、1300 oC、 1400 oC下燒結8小時，經XRD分析得知，沒有其他雜相產生。
以化學共沉法製備摻入各比例之鉛、鎳、銅、銀，經冷凍乾燥後，以1100 oC煆燒2小時，由XRD分析得知摻入少量的鉛、鎳、銅、銀並沒其他雜相出現。將煆燒後之產物壓錠，於1200 oC下燒結8小時。
由高阻抗儀在室溫下量測其直流阻抗與電壓的關係，發現鑭銦鎵氧化物在1400 oC下燒結之阻抗為1010 Ω-cm，1300 oC下燒結之阻抗為107 Ω-cm，1200 oC下燒結之阻抗為106 Ω-cm。摻入鉛、鎳、銅、銀可有效降低阻抗，且摻入量達0.8%時可得到較低之阻抗。其值分別為:2.41~7.07×106 Ω-cm、2.11~4.66×106 Ω-cm、1.48~3.10×106 Ω-cm、1.09~1.32×106 Ω-cm。
利用LCR測量儀在室溫下測量其電容值經公式換算成介電常數，得知鑭銦鎵氧化物1400 oC下燒結之介電常數為13~14，1300 oC下燒結之介電常數為14~17，1200 oC下燒結之介電常數為17~25。介電常數隨著燒結溫度和LCR量測頻率的升高而降低。摻入不同的元素可以使介電常數增加，摻入鉛之介電常數為22~31，摻入鎳之介電常數為35~49，摻入銅之介電常數為47~51，摻入銀之介電常數為59~67。

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.

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