Laminated Ceramic Capacitor Grain Growth Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laminated ceramic capacitors with thin dielectric ceramic layers experience excessive grain growth, leading to increased initial short circuit ratio and time degradation in insulation resistance during high-temperature load tests, particularly in layers thinner than 3 μm.
Innovation Solution
A laminated ceramic capacitor composition featuring Si, Mn, Al, V, and a perovskite-type compound with Sr, Ba, Zr, and optionally Ca, where the total content of Zr and Ti is 100 parts by mol, with specific molar ratios and crystal grain sizes of 1.2 μm or less, and using Ni or Ni alloy internal electrodes to reduce material costs and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dielectric ceramic layer thickness is reduced to 3 μm or less, then the capacitor size is reduced and capacitance density is improved, but grain growth is excessively promoted leading to increased initial short circuit ratio and insulation degradation
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of raw materials (BaOx-SrOy-CaOz with specific x, y, z values where x+y+z=1), adding specific amounts of additives (Mn3O4: 0.1-0.7 wt%, BaSiO3: 0.5-3.0 wt%, V2O5: 0.01-0.07 wt%, Al2O3: 0.05-0.30 wt%), and controlling sintering temperature and time to achieve grain sizes of 1.0 μm or less even in ultra-thin layers of 3 μm or less, thereby preventing excessive grain growth while maintaining small capacitor size
Solution Approach 2:
The patent uses composite materials by combining multiple oxide components (BaOx, SrOy, CaOz, Mn3O4, BaSiO3, V2O5, Al2O3) in specific proportions to form a complex dielectric ceramic composition that suppresses abnormal grain growth. This composite approach creates a synergistic effect where each component contributes to grain boundary control and sintering behavior, enabling reliable ultra-thin capacitor layers
2Ease of manufacture
If conventional dielectric ceramic composition is used, then manufacturing is simplified, but grain growth is promoted rapidly causing excessive grain sizes in thin layers which increases initial short circuit ratio and time degradation
Solution Approach 1:
The patent changes the compositional parameters by specifying precise ranges for each component (BaOx-SrOy-CaOz with controlled x, y, z ratios, specific additive concentrations) and sintering parameters (temperature, time, atmosphere) to achieve controlled grain growth. This allows grain size to be precisely controlled at 1.0 μm or less even in ultra-thin layers while maintaining a relatively simple layered manufacturing process
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 solution results in a highly reliable laminated ceramic capacitor with low initial short circuit ratio, excellent insulation degradation life, and extended high-temperature load life, even at reduced dielectric ceramic layer thicknesses, while maintaining low material costs.
Implementation Method 1
a perovskite-type compound containing Sr, Ba, Zr, Ti, and optionally containing Ca; when the total content of Zr and Ti is regarded as 100 parts by mol, (a) the total content m (parts by mol) of Sr, Ba, and Ca meets 100≦m≦105
Implementation Method 2
the crystal grains are 1.2 μm or less in average grain size
Implementation Method 3
the laminated body contains: Si, Mn, Al, V and a perovskite-type compound containing Sr, Ba, Zr, Ti, and optionally containing Ca
Implementation Method 4
a plurality of internal electrodes provided at a plurality of interfaces between the dielectric ceramic layers
Data Source
AI summary
A laminated body that contains a perovskite-type compound containing Sr, Ba, Zr, and Ti and containing; Si; Mn; Al; and V. When the total content of Zr and Ti is 100 parts by mol, the total content m of Sr and Ba meets 100≦m≦105, the Si content a meets 0.1≦a≦4.0, the Mn content b meets 0.1≦b≦4.0, the Al content c meets 0.01≦c≦3.0, the V content d meets 0.01≦d≦0.3, the molar ratio w of Sr and Ba to Sr meets 0.60≦w≦0.95, the molar ratio z of the total of Zr and Ti to Zr meets 0.92≦z≦0.98, w and y meets and the crystal grains are 1.2 μm or less in average grain size.