Hydrous Clay Crystallite Size Control for Shrinkage Management
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Solution Overview
Problem
Hydrous clay containing green monoliths experience significant shrinkage during firing, leading to cracks and defects in ceramic articles, and existing methods to control shrinkage either reduce the plasticity of the batch material or focus on overall clay particle shape rather than crystallite size.
Innovation Solution
Incorporating hydrous clay particles with a platy geometry and crystallite sizes greater than a predetermined amount, such as 80 nanometers, into ceramic precursor batch compositions to minimize shrinkage during firing, which is correlated with reduced defects and potential for faster firing cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the amount of hydrous clay is reduced to control shrinkage, then shrinkage is reduced, but the batch material becomes less plastic and more difficult to extrude
Solution Approach 1:
The patent changes the physical parameter of clay crystallite size rather than the quantity of clay. By controlling the crystallite size to be within a specific range (0.2-2.0 micrometers), the invention achieves shrinkage control while preserving the plasticity and extrudability of the batch material. This parameter change allows maintaining both manufacturing precision and ease of manufacture.
2Manufacturing precision
If the crystallite size of hydrous clay is increased to reduce shrinkage, then shrinkage and defects are reduced, but the characterization and measurement becomes more complex
Solution Approach 1:
The patent replaces complex mechanical characterization methods with X-ray diffraction (XRD) analysis. Instead of using sophisticated microscopy or direct measurement techniques to characterize crystallite size, the invention uses XRD peak broadening analysis, which is a more established and accessible analytical method. This substitution reduces the difficulty of detecting and measuring crystallite size while maintaining defect reduction benefits.
3Shape
If traditional clay characterization methods are used focusing on particle shape, then overall particle morphology is controlled, but shrinkage management is insufficient
Solution Approach 1:
The patent shifts focus from overall particle shape (global property) to internal crystallite size (local property) within the clay particles. By controlling the crystallite size specifically, while allowing particle morphology to remain traditional, the invention achieves better shrinkage control. This local quality approach allows maintaining desirable particle shapes while improving shrinkage management through internal structure control.
Data Source
AI summary
A method of making ceramic articles includes compounding ceramic precursor batch components that include hydrous clay. The hydrous clay includes particle components having a platy geometry. The crystallite size of the platy hydrous clay particle components is greater than a predetermined amount. Controlling such crystallite size can result in reduced shrinkage of green ware during the clay dehydroxylation stage of firing.