Percolative Ceramic Composite for High Dielectric Capacitors
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Solution Overview
Problem
Conventional approaches to achieving high dielectric constants in capacitors, such as multilayered ceramic capacitors and percolative composites, face challenges like size-dependent dielectric constant reduction and agglomeration issues with metal conductive phases, which hinder the production of materials with improved capacitance and structural integrity.
Innovation Solution
A ceramic sintered body is created by dispersing a semiconductor ceramic phase in a dielectric ceramic phase, forming a percolative composite with the semiconductor phase volume fraction close to but less than the percolation threshold, avoiding agglomeration and abnormal grain growth, thereby achieving a favorable dielectric constant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If metal conductive phases are used in percolative composites to achieve high dielectric constants, then capacitance is improved, but agglomeration and abnormal grain growth occur, deteriorating structural integrity
Solution Approach 1:
The patent changes the material parameter from metal conductive phase to semiconductor ceramic phase (e.g., from Ni to NiTiO3), which fundamentally alters the physical and chemical properties. This parameter change eliminates the agglomeration and abnormal grain growth issues associated with metal phases while maintaining the percolative composite structure and high dielectric constant, thus resolving the contradiction between capacitance improvement and structural integrity
Solution Approach 2:
The patent employs a composite material system consisting of semiconductor ceramic phase dispersed in dielectric ceramic matrix, forming a percolative composite. This composite structure allows the semiconductor phase to provide high dielectric constant and conductivity without the harmful effects of metal phases, while the dielectric matrix maintains structural stability, thereby achieving both high capacitance and structural integrity
2Volume of moving object
If capacitor size is reduced to improve integration, then device dimensions are improved, but dielectric constant tends to decrease, worsening capacitance
Solution Approach 1:
The patent uses percolative composite materials with semiconductor ceramic phase dispersed in dielectric ceramic matrix, which exhibit exceptionally high dielectric constants due to the percolative structure. This composite approach enables miniaturization of capacitors while maintaining or even enhancing dielectric constant, as the percolative network provides high capacitance in small volumes, thus resolving the contradiction between size reduction and dielectric constant maintenance
3Quantity of substance
If semiconductor ceramic phase volume fraction is increased to enhance dielectric constant, then capacitance is improved, but agglomeration occurs, worsening dispersion uniformity
Solution Approach 1:
The patent changes the material parameter from metal to semiconductor ceramic, which has different surface energy and sintering characteristics. This parameter change allows achieving percolative structure with improved dispersion uniformity, as the semiconductor ceramic phase does not exhibit the same agglomeration tendency as metal phases, enabling higher volume fractions to be achieved while maintaining uniform distribution
Solution Approach 2:
The patent creates a percolative composite structure where semiconductor ceramic phases are locally concentrated to form conductive networks while maintaining overall uniform dispersion in the dielectric matrix. This local quality approach allows the semiconductor phase to achieve percolation threshold for high dielectric constant while preventing excessive agglomeration, thus resolving the contradiction between dielectric constant enhancement and dispersion uniformity
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 successfully produces a ceramic sintered body with enhanced dielectric constant and structural strength, overcoming the limitations of conventional methods by maintaining even dispersion and preventing agglomeration, thus enabling improved capacitance without the drawbacks of metal-based percolative composites.
Implementation Method 1
the semiconductor ceramic phase and the dielectric ceramic phase jointly form a percolative composite, and a volume fraction of the semiconductor ceramic phase is close to and less than a percolation threshold
Implementation Method 2
a firing step of firing the green sheet in a reducing atmosphere to form the ceramic sintered body
Data Source
AI summary
The present disclosure provides a ceramic sintered body having a favorable dielectric constant. In some embodiments of the present disclosure, the ceramic sintered body includes a semiconductor ceramic phase dispersed in a dielectric ceramic phase, wherein the semiconductor ceramic phase and the dielectric ceramic phase jointly form a percolative composite, and a volume fraction of the semiconductor ceramic phase is close to and less than a percolation threshold.