Dielectric Ceramic Composition for Stable Capacitance Above 200°C
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Solution Overview
Problem
Current dielectric ceramic compositions fail to maintain excellent temperature properties and low DC bias dependence at high temperatures, particularly above 200°C, which is crucial for electronic components in electric vehicles and power modules.
Innovation Solution
A dielectric ceramic composition based on Ba(Ti(1-2x)RxWx)O3, where R is Mn and/or Mg, and x satisfies 0.06≤x≤0.10, is developed using a solid phase method involving multiple calcining and main-firing processes to produce a homogeneous system with no core-shell structure, enhancing capacitance-temperature stability and reducing DC bias attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional dielectric ceramic compositions are used, then manufacturing is simpler, but temperature properties deteriorate at 200°C or higher
Solution Approach 1:
The patent applies parameter changes by precisely controlling the substitution ratio x in the range of 0.06≤x≤0.10 for the Ba(Ti(1-2x)RxWx)O3 composition, where R is Mn and/or Mg. This specific parameter range optimizes the balance between temperature stability and manufacturing feasibility, achieving excellent capacitance-temperature characteristics at 200°C or higher without excessive manufacturing complexity.
Solution Approach 2:
The patent employs composite materials by creating a multi-element substituted barium titanate system Ba(Ti(1-2x)RxWx)O3 where Ti is simultaneously substituted by R (Mn and/or Mg) and W (tungsten). This composite structure combines the benefits of different elements to achieve superior high-temperature performance that single-element substitutions cannot provide.
2Reliability
If dielectric ceramic composition is optimized for low DC bias dependence, then capacitance stability improves, but temperature properties worsen at high temperatures
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the substitution ratio x to fall within 0.06≤x≤0.10. This specific parameter range simultaneously achieves low DC bias dependence (maintaining capacitance stability) and excellent temperature properties at 200°C or higher, whereas conventional compositions with different substitution ratios cannot achieve both properties concurrently.
Solution Approach 2:
The patent applies local quality by creating a homogeneous system where the dual substitution of Ti by R and W occurs uniformly throughout the ceramic structure. This uniform local composition ensures consistent electrical properties throughout the material, achieving both low DC bias dependence and stable temperature characteristics without the formation of core-shell structures that would create local inhomogeneities.
3Stability of the object's composition
If homogeneous system is achieved, then temperature properties improve, but manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by performing pre-mixing and pre-calcining of the raw materials (BaCO3, TiO2, R2O3, and WO3) before the main sintering process. This preliminary preparation ensures uniform distribution of all elements throughout the green body, facilitating the formation of a homogeneous system during main-firing while keeping the overall manufacturing process manageable and not excessively complex.
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 composition exhibits a low capacitance-temperature change rate and minimal dielectric constant change under DC bias, ensuring reliable performance up to 200°C and beyond, suitable for high-temperature electronic components like multilayer ceramic capacitors.
Implementation Method 1
first calcining BaCO3, TiO2 and oxide of R using a solid phase method
Implementation Method 2
first calcining BaCO3, TiO2 and oxide of R using a solid phase method
Implementation Method 3
mixing with WO3 and second calcining
Implementation Method 4
main-firing at least the base material and additives
Data Source
AI summary
Provided are a dielectric ceramic composition having excellent temperature properties and low DC bias dependence in a wide temperature range from room temperature to over 200° C., a method of manufacturing a dielectric ceramic composition, and a multilayer ceramic capacitor.