Ceramic body, honeycomb structure, method for producing ceramic body and heater element
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Solution Overview
Problem
Conventional ceramic bodies with PTC properties face challenges in achieving low room temperature electrical resistivity and high 200°C resistivity, particularly in honeycomb structures used for heater elements, where the distance between electrodes can lead to corrosion and require further reduced resistivity, and stable current interruption at abnormal temperatures.
Innovation Solution
A ceramic body based on BaTiO3 crystalline particles with partial substitution of Ba by rare earth and alkaline earth metal elements, specifically controlling the content of Ba6Ti17O40 crystalline particles and alkaline earth metal substitution to achieve low room temperature resistivity and 200°C resistivity 500 times higher, optimized through a method involving a forming step with ceramic raw materials and a firing process at controlled temperatures and heating rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the distance between electrodes is increased in honeycomb structures, then the structural integrity and heating uniformity are improved, but the electrical resistance increases leading to electrode corrosion and reduced efficiency
Solution Approach 1:
The patent changes the electrical resistance parameter of the ceramic material by controlling the content of Ba6Ti17O40 crystalline particles (1.0-8.0 mass%) and adjusting Ba substitution with alkaline earth metals (0.01-0.10 mol per 1 mol Ba). This reduces electrical resistance to prevent electrode corrosion while maintaining structural integrity through optimized material composition
2Use of energy by moving object
If the room temperature electrical resistivity is reduced to improve heating efficiency, then the heat generation performance is improved, but the ability to interrupt current at abnormal temperatures may be compromised
Solution Approach 1:
The patent optimizes the PTC characteristic parameters by controlling Ba substitution with rare earth and alkaline earth metals, and adjusting Ba6Ti17O40 crystalline particle content. This creates a material with low room temperature resistivity for efficient heating while maintaining high 200°C resistivity (500 times higher) for reliable current interruption
Solution Approach 2:
The patent creates a composite ceramic material combining BaTiO3-based crystalline particles with controlled Ba6Ti17O40 phase. This composite structure achieves both low room temperature resistivity and high temperature resistivity, balancing heating efficiency and safety
3Quantity of substance
If the substitution amount of Ba with alkaline earth metal is increased to reduce room temperature resistivity, then the electrical conductivity is improved, but the sintering stability and Curie point control become more difficult
Solution Approach 1:
The patent precisely controls the substitution amount of Ba with alkaline earth metals within 0.01-0.10 mol per 1 mol Ba, and maintains Ba6Ti17O40 crystalline particle content at 1.0-8.0 mass%. This optimized parameter range achieves improved electrical conductivity while maintaining sintering stability and Curie point control
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 approach results in a ceramic body with significantly reduced room temperature resistivity and increased 200°C resistivity, suitable for efficient heat generation and current interruption, enhancing the performance of honeycomb structures as heater elements while preventing electrode corrosion.
Implementation Method 1
a ceramic body obtained by adding various additive elements to a composition represented by BaTiO3 is proposed as a material exhibiting a PTC (Positive Temperature Coefficient) property. The PTC property is a property in which a resistant value is rapidly increased at elevated temperature that is higher than or equal to a Curie point.
Implementation Method 2
The ceramic body having the PTC property have been used for PTC heaters
Data Source
AI summary
A ceramic body mainly based on BaTiO3-based crystalline particles in which a part of Ba is substituted with at least one rare earth element and at least one alkaline earth metal element. The ceramic body contains from 1.0 to 8.0% by mass of Ba6Ti17O40 crystalline particles. The BaTiO3-based crystal particles have a substituted amount of one mol of the Ba with the alkaline earth metal element of 0.01 to 0.10 mol.