晶界偏析对CaCu_3Ti_4O_(12)陶瓷介电性能的影响
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摘要
采用溶胶凝胶法制备Ca Cu_3Ti_4O_(12),通过球磨对陶瓷样品进行处理,探究此处理方法对Ca Cu_3Ti_4O_(12)介电性能的影响.研究结果表明,球磨对Ca Cu_3Ti_4O_(12)陶瓷样品的介电常数有较大影响.随着球磨时间的增加,样品介电常数显著增加,当球磨时间为4 h,其室温下介电常数可达10~6量级,比未经球磨处理的样品高2个数量级,且随温度升高,介电常数显著增大.温度上升100 K,介电常数约提高一个数量级.同时SEM分析表明,球磨处理Ca Cu_3Ti_4O_(12)样品介电常数的增大与其晶界偏析有较大的关系,特别是晶界处析出的Cu O二次相可极大地提升Ca Cu_3Ti_4O_(12)的极化率,可提高约2个数量级.
The polarizability of dielectric material is sensitive to microstructures,including grain size,grain boundary and the segregationphase at grain boundary.In this work,ceramic Ca Cu_3Ti_4O_(12)was prepared by sol-gel method with a post ball milling.The influence of milling treatment on dielectric properties of Ca Cu_3-Ti_4O_(12)ceramics was investigated.Experimental results indicate that the dielectric constant of Ca Cu_3Ti_4O_(12)ceramic sample is greatly affected by the ball milling.The dielectric constant of Ca Cu_3Ti_4O_(12)increases with increasing the milling time,obviously.When the milling time is 4 hours,the constant can reach a value of10~6,much higher than that of the untreated sample.The dielectric constant increases by an order of magnitude with increasing temperature by 100 K.Besides,SEM analysis indicates that the increase of the dielectric constant is related to the grain boundary segregation of Ca Cu_3Ti_4O_(12),especially the secondary phase of Cu O precipitated at grain boundaries can greatly enhance the polarization of Ca Cu_3Ti_4O_(12)by around two order of magnitude.
The polarizability of dielectric material is sensitive to microstructures,including grain size,grain boundary and the segregationphase at grain boundary.In this work,ceramic Ca Cu_3Ti_4O_(12)was prepared by sol-gel method with a post ball milling.The influence of milling treatment on dielectric properties of Ca Cu_3-Ti_4O_(12)ceramics was investigated.Experimental results indicate that the dielectric constant of Ca Cu_3Ti_4O_(12)ceramic sample is greatly affected by the ball milling.The dielectric constant of Ca Cu_3Ti_4O_(12)increases with increasing the milling time,obviously.When the milling time is 4 hours,the constant can reach a value of10~6,much higher than that of the untreated sample.The dielectric constant increases by an order of magnitude with increasing temperature by 100 K.Besides,SEM analysis indicates that the increase of the dielectric constant is related to the grain boundary segregation of Ca Cu_3Ti_4O_(12),especially the secondary phase of Cu O precipitated at grain boundaries can greatly enhance the polarization of Ca Cu_3Ti_4O_(12)by around two order of magnitude.
引文
[1]Ramirez A P,Subramanian M A,Gardel M,et al.Giant dielectric constant response in acopper-titanate[J].Solid Stat Commun,2000,115:217.
[2]Subramanian M A,Li D,Duan N,et a1.High dielectric constant in ACu3Ti4O12and ACu3Ti3Fe O12phases[J].J Solid State Chem,2000,151:323-325.
[3]Adams T B,Sinclair D C,West A R,et al.Giant barrier layer capacitance effects in Ca Cu3Ti4O12ceramics[J].Adv Mater,2002,14:1321.
[4]Sinclair D C,Adams T B,Morrison F D,et al.Ca Cu3Ti4O12:One-step internal barrier layer capacitor[J].Appl Phys Lett,2002,80:2153.
[5]Adams T B,Sinclair D C.Characterization of grain-boundary impedances in fine andcoarse-grained Ca Cu3Ti4O12ceramics[J].Phys Rev B,2006,73:094124.
[6]Shao S F,Zhang J L.Microstructure and electrical properties of Ca Cu3Ti4O12ceramics[J].J Appl Phys,2006,99:084106.
[7]Zhang J L,Zheng P,Wang C L.Dielectric dispersion of Ca Cu3Ti4O12ceramicsat high temperatures[J].Appl Phys Lett,2005,87:142898-142901.
[8]Lunkenheimer P,Fichtl R,Ebbinghaus S G,et al.Nonintrinsic origin of the colossal dielectric constants in Ca Cu3Ti4O12[J].Phys Rev B,2004,70:172102.
[9]Li J,Sleight A W,Subramanian M A.Evidence for internal resistive barriers in a crystal of the giant dielectric constant material:Ca Cu3Ti4012[J].Solid State commu,2005,135:260.
[10]杨静,沈明荣,方亮.电极对Ca Cu3Ti4012陶瓷介电性能的影响[J].功能材料,2006,37(2):234-237.
[11]Capsoni D,Bini M,Massarotti V,et al.Role of doping and Cu O segregation in improving the giant permittivity of Ca Cu3Ti4O12[J].J Solid State Chem,2004,177:4494-4500.
[12]Yuan W X,Luo Z K,Wang C D.Investigation on effects of Cu O secondary phase on dielectric properties of Ca Cu3Ti4O12ceramics[J].J Alloys Comp,2013,562:1-4.
[13]Mohamed J J,Hutagalung S D,Ahmad Z A.Influence of sintering parameters on melting Cu O phase in Ca Cu3Ti4O12[J].J King Saud University Engineering Sciences,2013,25:35-39.
[14]Sonia De,Almeida Didry,Cecile Autret,et al.Leading role of grain boundaries in colossal permittivity of doped and undoped CCTO[J].J Eur Ceram Soc,2014,34:3649-3654.
[15]Manik S K,Pradhan S K.Microstructure characterization of ball-mill-prepared nano-crystalline Ca Cu3Ti4O12by Rietveld methed[J].Phys E,2006,33:160-168.
[2]Subramanian M A,Li D,Duan N,et a1.High dielectric constant in ACu3Ti4O12and ACu3Ti3Fe O12phases[J].J Solid State Chem,2000,151:323-325.
[3]Adams T B,Sinclair D C,West A R,et al.Giant barrier layer capacitance effects in Ca Cu3Ti4O12ceramics[J].Adv Mater,2002,14:1321.
[4]Sinclair D C,Adams T B,Morrison F D,et al.Ca Cu3Ti4O12:One-step internal barrier layer capacitor[J].Appl Phys Lett,2002,80:2153.
[5]Adams T B,Sinclair D C.Characterization of grain-boundary impedances in fine andcoarse-grained Ca Cu3Ti4O12ceramics[J].Phys Rev B,2006,73:094124.
[6]Shao S F,Zhang J L.Microstructure and electrical properties of Ca Cu3Ti4O12ceramics[J].J Appl Phys,2006,99:084106.
[7]Zhang J L,Zheng P,Wang C L.Dielectric dispersion of Ca Cu3Ti4O12ceramicsat high temperatures[J].Appl Phys Lett,2005,87:142898-142901.
[8]Lunkenheimer P,Fichtl R,Ebbinghaus S G,et al.Nonintrinsic origin of the colossal dielectric constants in Ca Cu3Ti4O12[J].Phys Rev B,2004,70:172102.
[9]Li J,Sleight A W,Subramanian M A.Evidence for internal resistive barriers in a crystal of the giant dielectric constant material:Ca Cu3Ti4012[J].Solid State commu,2005,135:260.
[10]杨静,沈明荣,方亮.电极对Ca Cu3Ti4012陶瓷介电性能的影响[J].功能材料,2006,37(2):234-237.
[11]Capsoni D,Bini M,Massarotti V,et al.Role of doping and Cu O segregation in improving the giant permittivity of Ca Cu3Ti4O12[J].J Solid State Chem,2004,177:4494-4500.
[12]Yuan W X,Luo Z K,Wang C D.Investigation on effects of Cu O secondary phase on dielectric properties of Ca Cu3Ti4O12ceramics[J].J Alloys Comp,2013,562:1-4.
[13]Mohamed J J,Hutagalung S D,Ahmad Z A.Influence of sintering parameters on melting Cu O phase in Ca Cu3Ti4O12[J].J King Saud University Engineering Sciences,2013,25:35-39.
[14]Sonia De,Almeida Didry,Cecile Autret,et al.Leading role of grain boundaries in colossal permittivity of doped and undoped CCTO[J].J Eur Ceram Soc,2014,34:3649-3654.
[15]Manik S K,Pradhan S K.Microstructure characterization of ball-mill-prepared nano-crystalline Ca Cu3Ti4O12by Rietveld methed[J].Phys E,2006,33:160-168.