Investigations On The Preparation Of Copper Inner Electrode Paste For LTCC And The Energy Storage Characteristics Of （PbLaSr）（ZrTi）O₃ Ceramics

In this thesis,the conductive copper paste used as inner electrode for LTCC（Low Temperature Co-fired ceramic）technology with and PLSZT ceramics with high energy storage properties were mainly investigated.The influence of chemical treatment on the dispersity and reducibility of copper powder was studied.The optimal ratios of the compositions of copper paste were determined in terms of the orthogonal experimental design.In addition,The performance differences of the PLSZT ceramics prepared by high-energy ball milling and ordinary ball milling were also explored.The actual contents and output are outlined as follows.（1）PVP,Tween 80 and butyl phosphate were used as dispersants,and both chemical and physical methods were employed to treat the copper powders.In terms of the orthogonal experimental design,it was determined that the copper powders showed the best dispersion effect when the PVP used as the dispersant,copper powder:PVP=20:3,and ultrasonication for 180 min.The untreated copper powder was reduced using the trisodium citrate.When the copper powder:trisodium citrate=16:3,the effect was the best.The XRD patterns indicated that only the specific diffraction peak of pure copper occurred,and no impact on the quality of the copper powders was observed.（2）The influence of organic carrier,ethyl cellulose,on the viscosity of slurry was investigated.It was determined that the viscosity of the slurry prepared was 195.11 Pa·s when the dosage of ethyl cellulose was 3 wt%,and its rheology and screen printing performance were good.The orthogonal experimental design method was used to seek for the optimal composition of the copper paste.It was procured that the optimized conditions,i,e.,copper powder:glass powder:organic carrier=71:3:26.The prepared copper paste exhibited excellent electrical conductivity,suitable viscosity and good screen printing performance.The sintered copper film revealed a dense morphology with a viscosity of 193.76 Pa·s and a square resistance of2.5 mΩ/□.（3）The PLSZT powders were prepared using high-energy ball milling and ordinary ball milling.It was observed that the powders size and the grain sizes of the ceramics could be effectively reduced using the high-energy ball milling.The average grain size of the ceramics prepared using the high-energy ball milling derived powders was 0.85μm,which also could PLSZTwithstand an electric field up to 200 kV/cm,higher than the 120 kV/cm of ceramics using ordinary ball milling derived powders.Moreover,the discharge energy density PLSZT is 2.92 J/cm~3,and the energy storage efficiency is 89.1%at 200 kV/cm.And the ceramics showed good temperature stability and frequency stability of the energy storage performance.