Ceramic Capacitor Metal Electrode with In-Situ BaTiO3 Dispersion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for forming metal electrodes in ceramic capacitors face issues with discontinuity and non-uniformity due to the agglomeration of barium titanate powders in nickel slurry, leading to stress-induced shrinkage and poor electrode continuity.
Innovation Solution
A method involving the use of barium titanate organic-precursor mixed with metal powders, followed by a binder burn-out process to transform the precursor into barium titanate, which is then dispersed homogeneously, combined with a sintering process to form a continuous metal electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If barium titanate powders are added into nickel slurry to improve electrode continuity, then electrode discontinuity is reduced, but the barium titanate powders agglomerate and fail to disperse homogeneously
Solution Approach 1:
The patent uses an organic precursor as an intermediary substance between barium titanate and nickel powders. The organic precursor contains both barium and titanate elements in molecular form, allowing homogeneous mixing with nickel powders before decomposition. This intermediary approach prevents agglomeration of inorganic barium titanate particles while ensuring uniform distribution, resolving the contradiction between improving electrode continuity and maintaining mixture homogeneity.
Solution Approach 2:
The patent changes the physical and chemical parameters of barium titanate by converting it from inorganic powder form to organic precursor form. This parameter change enables better dispersion and homogeneity in the slurry. The organic precursor decomposes during sintering to form barium titanate in-situ, ensuring both homogeneous distribution and continuous electrode structure without the agglomeration problems of direct powder addition.
2Strength
If nickel powders are densified at high temperature to improve electrode strength, then electrode density increases, but thermal stress causes shrinkage and discontinuity
Solution Approach 1:
The patent performs preliminary action by incorporating barium titanate organic precursor into the nickel slurry before sintering. During the heating process, the organic precursor decomposes and forms barium titanate particles in-situ within the nickel matrix. This preliminary formation of barium titanate prevents thermal stress-induced shrinkage and maintains thickness uniformity during the densification process, as the barium titanate acts as a buffer against thermal expansion mismatches.
3Strength
If sintering temperature is increased to complete densification of nickel electrodes, then electrode density improves, but barium titanate begins to densify causing compressive stress and nickel shrinkage
Solution Approach 1:
The patent creates a composite material system where nickel and barium titanate are combined at the micro-level through the organic precursor approach. The resulting composite electrode structure has nickel providing electrical conductivity and barium titanate providing mechanical stability and stress buffering. This composite approach allows simultaneous densification of both materials at high sintering temperatures while managing thermal stresses, as the barium titanate particles distributed within the nickel matrix prevent excessive shrinkage and maintain structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method enhances electrode continuity and reduces shrinkage, improving thickness uniformity and increasing the mean time to failure (MTTF) of the ceramic capacitors.
Implementation Method 1
performing a binder burn-out process to the film material to obtain a degumming film; and performing a sintering process to the degumming film to obtain the metal electrode. Based on an amount of the metal powders as 100 wt %, an amount of the barium titanate organic-precursor is 3 wt % to 15 wt %. The above binder burn-out process makes the barium titanate-organic precursor transform to barium titanate.
Implementation Method 2
performing a sintering process to the degumming film to obtain the metal electrode
Data Source
AI summary
A metal electrode of a ceramic capacitor and a method of forming the same are provided. The method includes mixing metal powders and a barium titanate organic-precursor to obtain precursor powders; adding an adhesive to the precursor powders to obtain a metal slurry; performing a molding process to the metal slurry to obtain a film material; performing a binder burn-out process to the film material to obtain a degumming film; and performing a sintering process to the degumming film to obtain the metal electrode. By mixing specific amount of barium titanate organic-precursor with the metal powders, the barium titanate metallic organic-precursor can be transformed to barium titanate in the following process, and barium titanate can be dispersed between the metals homogeneously. Therefore, electrode continuity can be increased.