Ceramic Capacitor Electrode Paste Sintering Match
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Solution Overview
Problem
Existing methods for manufacturing ceramic electronic elements, such as laminated ceramic capacitors, face issues with the discontinuity of inner electrode layers due to uneven sintering of electrode paste, leading to reduced electrostatic capacity and adhesion between dielectric and electrode layers, which is exacerbated by the addition of insulating materials to match firing temperatures.
Innovation Solution
Incorporating a ceramic dielectric powder and a metal resinate into the electrode paste, along with a metal powder, to form a laminate structure that improves the continuity of inner electrode layers while maintaining adhesion and function, by adjusting the sintering start temperature and shrinkage ratio to match that of the ceramic article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If common material (insulating ceramic powder) is added to electrode paste to match firing temperature and shrinkage ratio, then sintering start temperature and shrinkage ratio of electrode paste approach those of ceramic article, but the function of inner electrode layer as electrode deteriorates due to insulating material
Solution Approach 1:
The patent introduces a metal binder as an intermediary substance that replaces insulating ceramic powder in the electrode paste. This metal binder serves dual functions: it acts as a binding agent during the green state and transforms into conductive metal particles after firing, thereby maintaining electrode functionality while enabling better matching of sintering characteristics between electrode paste and ceramic article.
Solution Approach 2:
The patent changes the chemical composition parameters of the electrode paste by substituting insulating ceramic powder with metal binder containing reactive metal particles. This parameter change transforms the paste from insulating to conductive after firing, resolving the contradiction between matching sintering characteristics and maintaining electrode function.
2Temperature
If metal resinate is added to electrode paste to raise sintering start temperature, then sintering start temperature increases, but shrinkage ratio becomes much greater than ceramic article due to low metal component volume ratio, lowering adhesion between dielectric and electrode layers
Solution Approach 1:
The patent creates a composite electrode paste material combining metal powder, metal binder, and organic vehicle. This composite formulation achieves balanced shrinkage characteristics by incorporating ceramic powder at controlled proportions, preventing excessive shrinkage while maintaining raised sintering temperature, thereby preserving interlayer adhesion.
Solution Approach 2:
The patent applies different material compositions to different functional requirements within the electrode paste: metal powder provides conductivity and structural framework, metal binder provides binding and controlled shrinkage, and ceramic powder provides sintering temperature matching. This local quality differentiation resolves the contradiction between temperature matching and adhesion maintenance.
3Temperature
If electrode paste is fired at high temperature to match ceramic article sintering, then sintering temperature match is achieved, but electrode paste aggregates with uneven metal component distribution, causing discontinuous inner electrode layers and reduced electrostatic capacity
Solution Approach 1:
The patent performs preliminary mixing of metal powder, metal binder, and organic vehicle to create a homogeneous paste composition before firing. This preliminary action ensures uniform distribution of metal components throughout the paste, preventing aggregation during firing and ensuring continuous electrode layer formation at high temperatures.
Solution Approach 2:
The patent replaces mechanical mixing methods with chemical bonding mechanisms through the metal binder. The binder creates a matrix that holds metal particles in fixed positions, substituting mechanical agitation with chemical stabilization, thereby preventing particle aggregation during the firing process and ensuring layer continuity.
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
This approach enhances the continuity of inner electrode layers, suppresses the decrease in adhesion between dielectric and electrode layers, and maintains the electrode functions, resulting in improved electrostatic capacity and stability of the ceramic electronic element.
Implementation Method 1
fine metal particles of the metal resinate are generated between the metal components of the electrode paste at the time of firing the laminate
Implementation Method 2
the electrode paste has a sintering start temperature lower than that of the ceramic article and dielectric paste. Therefore, when the laminate is heated for firing, the electrode paste starts sintering earlier than the ceramic article does
Implementation Method 3
drying the organic solvent contained in the electrode paste
Data Source
AI summary
A ceramic electronic element having improved the continuity of inner electrode layers while suppressing the decrease in adhesion between its dielectric layers and inner electrode layers and the deterioration in functions of the inner electrode layers, and a method of making the same are provided. In the method of making a ceramic capacitor (10) in accordance with the present invention, an electrode paste (22) is applied to a surface (20a) of a green sheet (20) and fired, so as to form a dielectric layer (12) laminated with an electrode layer (14). Since the electrode paste (22) is doped with a BaTiO3 powder, the adhesion between the dielectric layer (22) and inner electrode layer (14) after firing is significantly restrained from lowering, and the sintering start temperature of the electrode paste (22) is close to that of the green sheet (20). Since the electrode paste (22) is doped with a metal resinate, functions of the inner electrode layer (14) are significantly restrained from deteriorating when the insulating BaTiO3 powder is added to the electrode paste (22), and the sintering start temperature of the electrode paste (22) approaches that of the green sheet (20).