Cement Mixture for Plugging Honeycomb Filter Bodies
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Solution Overview
Problem
Current cement mixtures for plugging honeycomb bodies often result in stuck ceramic filter bodies during firing, making separation difficult and potentially damaging, which increases processing time and costs.
Innovation Solution
A cement mixture comprising at least 50% refractory material such as alumina or zirconia and less than 15% titania, along with a pore forming agent and organic binder, is used to plug green honeycomb bodies, allowing for stacking and single-step firing while minimizing sticking between stacked structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional cement mixtures are used to plug green honeycomb bodies, then the honeycomb structures are firmly held during firing, but the structures stick together after firing making separation difficult and potentially damaging
Solution Approach 1:
The invention changes the chemical composition parameters of the cement mixture by limiting titania to less than 15% and specifying ranges for alumina (40-70%) and zirconia (20-40%), which fundamentally alters the firing behavior and sticking characteristics of the plug material
Solution Approach 2:
The invention uses a composite cement mixture containing multiple refractory materials (alumina, zirconia, silica, magnesia) in specific proportions, creating a material that balances holding strength during firing with reduced sticking after firing, unlike conventional single-material plugs
2Ease of operation
If conventional cement mixtures with higher titania content are used, then the mixture has better flowability and filling properties, but the honeycomb structures experience increased sticking during firing
Solution Approach 1:
The invention inverts the conventional approach by strictly limiting titania content to less than 15% (conventionally higher), and instead achieves flowability and filling properties through optimized combinations of alumina, zirconia, and fine particle content while eliminating the harmful sticking effect
3Ease of operation
If the cement mixture formulation is optimized for reduced sticking, then separation becomes easier, but the holding strength during firing may be compromised
Solution Approach 1:
The invention creates a multi-component composite cement mixture where alumina provides structural strength, zirconia enhances refractory properties and reduces sticking, silica contributes to flowability, and magnesia prevents excessive sintering, achieving both strong holding during firing and easy separation after firing
Solution Approach 2:
The invention optimizes the local chemical composition at the interface between the plug and honeycomb structure, with specific particle size distributions and refractory material concentrations that promote strong bonding during firing but prevent excessive adhesion after cooling
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 proposed cement mixture reduces the sticking between stacked honeycomb structures after firing, enabling easier separation with less force and damage, thus improving processing efficiency and reducing material utilization costs.
Implementation Method 1
heating the first plugged green honeycomb structure to a first temperature to convert the ceramic precursor material and the cement mixture into a sintered phase ceramic material
Data Source
AI summary
A cement mixture for application to a honeycomb body and a method of forming a plugged ceramic honeycomb body is provided. The cement mixture contains a plurality of inorganic particles including at least about 50% of a refractory material selected from at least one of alumina and zirconia and less than about 15% titania (by weight), a pore forming agent, an organic binder, and a liquid vehicle.