Ceramic Honeycomb Cement Skin Composition for Crack Resistance
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Solution Overview
Problem
Cement compositions applied to ceramic honeycombs are prone to cracking during processing and under temperature fluctuations, leading to rejection or reduced performance.
Innovation Solution
A cement composition comprising specific ratios of inorganic particles with varying sizes, an inorganic fibrous material, and a water-soluble organic binder, which reduces cracking and enhances thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cement skin composition is applied to ceramic honeycomb and dried in heated conditions, then the cement skin forms a protective outer layer, but cracks occur during processing and under temperature fluctuations
Solution Approach 1:
The patent changes the chemical composition parameters of the cement skin by incorporating specific amounts of glass particles (2-10 wt%), ceramic particles (5-20 wt%), and metal particles (1-5 wt%) to modify the thermal expansion coefficient and reduce cracking during heating and drying processes
Solution Approach 2:
The patent creates a composite cement skin material combining multiple particle types (glass, ceramic, metal) with the cement binder to achieve improved crack resistance while maintaining structural integrity under thermal stress
2Strength
If cement skin is applied to protect ceramic honeycomb, then structural integrity is improved, but the skin weakens and cracks under high temperatures and thermal shock
Solution Approach 1:
The patent modifies the thermal stability by adjusting the composition ratios of temperature-resistant particles (glass, ceramic, metal) to match the thermal expansion properties of the underlying ceramic honeycomb, preventing differential stress and cracking at high temperatures
Solution Approach 2:
The patent utilizes thermal expansion principles by selecting particle materials with coefficients of thermal expansion compatible with both the cement binder and the ceramic honeycomb substrate, reducing thermal stress during temperature fluctuations
Data Source
AI summary
A cement composition for application to a ceramic substrate, such as a cement skin composition for application to a ceramic honeycomb body is provided. The cement composition includes a first source of inorganic particles, a second source of inorganic particles having a mean particle diameter<50 nm, wherein the first source of inorganic particles is present at about ≤15% (by dry weight), a second source of inorganic particles having a mean particle diameter of from about 50 nm to about 700 nm, wherein the second source of inorganic particles is present at from about 5% to about 15% (by dry weight), and a water-soluble organic binder. An inorganic fibrous material can be present at about ≤15% (based on dry weight). The amount of at least one of the first source of inorganic particles or the inorganic fibrous material is greater than 0% (by dry weight).