Effect of Cr doping on secondary phases and electrical properties of zinc oxide ceramic thick film varistors

【摘要】 In order to get high-performance low voltage varistors,Cr2O3 doped ZnO ceramic thick films were fabricated by modified sol-gel process. The precursors were fabricated by dispersing doped-ZnO ceramic nano-powders in the sols,which were prepared by dissolving zinc acetate dihydrate into 2-methoxyethanol and stabilized by diethanolamine and glacial acetic acid and doped with a concentrated solution of bismuth nitrate,phenylstibonic acid,cobalt nitrate,manganese acetate and chromium nitrate. The results show that ZnCr2O4 phase can form in ZnO based ceramic films doped 1.0%(mole fraction) Cr2O3. Three secondary phases,such as Bi2O3,Zn7Sb2O12,and ZnCr2O4 phases,are detected in the thick films. The Raman spectra show that the intensity and the position of Raman bands of Zn7Sb2O12 and ZnCr2O4 phases change obviously with increasing Cr2O3 doping. The nonlinearity coefficient α of ZnO thick films is 7.0,the nonlinear voltage is 6 V,and the leakage current density is 0.7 μA/mm2.更多还原

【Abstract】 In order to get high-performance low voltage varistors,Cr2O3 doped ZnO ceramic thick films were fabricated by modified sol-gel process. The precursors were fabricated by dispersing doped-ZnO ceramic nano-powders in the sols,which were prepared by dissolving zinc acetate dihydrate into 2-methoxyethanol and stabilized by diethanolamine and glacial acetic acid and doped with a concentrated solution of bismuth nitrate,phenylstibonic acid,cobalt nitrate,manganese acetate and chromium nitrate. The results show that ZnCr2O4 phase can form in ZnO based ceramic films doped 1.0%(mole fraction) Cr2O3. Three secondary phases,such as Bi2O3,Zn7Sb2O12,and ZnCr2O4 phases,are detected in the thick films. The Raman spectra show that the intensity and the position of Raman bands of Zn7Sb2O12 and ZnCr2O4 phases change obviously with increasing Cr2O3 doping. The nonlinearity coefficient α of ZnO thick films is 7.0,the nonlinear voltage is 6 V,and the leakage current density is 0.7 μA/mm2.更多还原