Titanium Core-Shell Powder for MLCC Dielectric Layers
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Solution Overview
Problem
Conventional barium titanate powders with small particle sizes tend to aggregate, hindering the formation of thin dielectric layers in multi-layer ceramic capacitors, which results in low capacitance constants due to the loose structure of the dielectric shell in core-shell particles.
Innovation Solution
A titanium-containing core-shell powder is developed, comprising a conductive core body and a shell layer of titanate oxides with perovskite or spinel structures, chemically bonded to each other, where the shell layer is formed through a calcination process involving a titanium compound powder and an inorganic salt powder, allowing for interbonding of shell layers during sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If barium titanate powder with small particle size is used to obtain thinner dielectric layer, then the dielectric layer thickness is reduced, but the powder aggregates into large particles which hinders thin layer formation
Solution Approach 1:
The dielectric layer is constructed using core-shell particles where the shell is divided into multiple dielectric sub-particles attached to a conductive core body. This segmentation prevents aggregation while maintaining thin layer formation capability.
Solution Approach 2:
The invention uses composite core-shell particles combining a conductive core body with a dielectric shell layer. This composite structure prevents particle aggregation while enabling thin dielectric layer formation and high capacitance constant.
2Stability of the object's composition
If shell is formed from dielectric sub-particles to prevent aggregation, then particle stability is improved, but the shell has loose structure which reduces capacitance constant
Solution Approach 1:
The invention changes the structural parameters of the shell by forming a dense crystalline structure through controlled reaction between titanium compound powder and inorganic salt powder, rather than using loosely attached sub-particles. This increases the capacitance constant while maintaining stability.
Solution Approach 2:
The shell layer is formed with different local properties: a dense crystalline structure for high capacitance constant, while the core-shell configuration provides overall particle stability. The chemical bonding between core and shell ensures local structural integrity.
3Ease of manufacture
If core body is made electrically conductive to enable shell formation, then shell encapsulation is achieved, but the overall particle complexity increases
Solution Approach 1:
The core-shell structure embeds the conductive core body within the dielectric shell layer, creating a nested configuration that simplifies the manufacturing process while achieving effective encapsulation. The simple spherical geometry reduces structural complexity.
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 enables the formation of a sintered body with enhanced capacitance by preventing aggregation and achieving a stable, interbonded shell structure, thereby improving the capacitance constant of multi-layer ceramic capacitors.
Implementation Method 1
subjecting the preformed powder to calcination to cause solid-state reaction of particle surfaces of the titanium compound powder with the inorganic salt powder to form a titanium compound-containing crystalline shell layer
Implementation Method 2
The shell layers of adjacent ones of the core-shell particles are interbonded to one another through the sintering process
Data Source
AI summary
A titanium compound-containing core-shell powder includes a plurality of core-shell particles, each of which includes a core body and a shell layer encapsulating said core body. The core body is electrically conductive. The shell layer includes a crystal that is selected from titanate oxides having a perovskite structure and titanate oxides having a spinel structure. The core body and the shell layer are chemically bonded to each other.