Firing Cycle Control for Ceramic Substrate Pore Size Distribution
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Solution Overview
Problem
Current methods struggle to effectively control pore size distribution in ceramic substrate articles, which affects porosity and thermal shock resistance, particularly in automotive filter substrates, where larger mean pore sizes are desired for improved thermal shock resistance and water absorption characteristics.
Innovation Solution
The method involves selecting a batch composition and calculating specific heating rates for the firing cycle to achieve desired pore size distributions, with temperature ranges and heating rates optimized to produce ceramic articles with median pore diameters greater than or equal to 5 micrometers, using formulas to determine the firing cycle parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional firing methods are used, then manufacturing process is simple, but pore size distribution cannot be precisely controlled
Solution Approach 1:
The patent applies parameter changes by systematically varying heating rates across different temperature ranges (950-1050°C, 1050-1150°C, 1150-1250°C, 1250-1350°C) to control pore size distribution. By adjusting heating rate parameters in specific ranges, the method achieves precise control over pore size properties including median pore diameter and pore size distribution characteristics, transforming the firing process into a controllable parameter-based system.
2Reliability
If larger mean pore sizes are produced, then thermal shock resistance improves, but porosity control becomes more difficult
Solution Approach 1:
The patent segments the firing process into four distinct temperature ranges, each with optimized heating rates. This segmentation allows independent control of pore formation mechanisms at different stages: 950-1050°C for initial pore development, 1050-1150°C for pore growth, 1150-1250°C for pore coarsening, and 1250-1350°C for final pore structure stabilization. Through this segmented approach, the method achieves both large mean pore sizes for thermal shock resistance and consistent porosity control.
Solution Approach 2:
The patent incorporates feedback mechanisms through predictive models that calculate required heating rates based on desired pore size distributions. The model uses relationships between temperature, time, and pore size properties to adjust firing parameters in real-time, ensuring consistent porosity and thermal shock resistance while maintaining control over the firing 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
This approach allows for precise control of pore size distribution, enhancing thermal shock resistance by up to 200°C and maintaining consistent porosity, thereby improving the performance of ceramic substrates in applications like automotive filters.
Implementation Method 1
calculating a heating-rate for firing the green body precursor
Implementation Method 2
firing a green body precursor
Data Source
AI summary
A method for producing high porosity ceramic substrate articles including a fire-cycle or firing schedule that includes fast-heating rates, as defined herein.