Development of Y5V Dielectric Powder Formulation for Reducing Atmosphere Sintering by Solid State Reaction Method

• Main Authors: En-Dao Liu, 劉恩道
• Other Authors: Jakob Soong
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/16194919983519848509

碩士 === 義守大學 === 材料科學與工程學系 === 91 === It is trends that multilayer ceramic capacitors (MLCC) with base metal inner electrode will substitute for other capacitors in market gradually. These capacitors must be fired in reducing atmosphere to protect nickel electrode from oxidation. The main powder formulation with barium titanate creates oxygen vacancy in reducing atmosphere. That vacancy could be moved by electric field to make barium titanate powders in dielectric layers resulting in semiconducting. For this reason, the additions of donor and acceptor simultaneously will form complex to solve conducting and reliability problems. Use traditional solid state methods to prepare barium titanate based Y5V powder formulation in the system of [(Ba0.996Ca0.004)O] 1.004[(Ti0.82Zr0.18)O2]. The formulation has high dielectric constant and very popular in the market. We can compare difference by varying atmosphere and different ratio of ytterbium cation and magnesium cation in the powder. The effect could be studied in electric properties and microstructure. Elements distribution could be investigated by TEM and EPMA. The results indicated that 1.0at% ytterbium cation formulation has better dielectric constant and insulation resistance in reducing sintering, and 0.1 at% ytterbium cation and 0.3 at% magnesium cation simultaneously formulation also has same result. These compositions meet Y5Vspecification in EIA, owing to complex composed of donor and acceptor. We can further study microstructure in multilayer ceramic capacitors by SEM and diffusion of nickel from electrode into the active dielectric layers by use of TEM and EPMA.