CMC Slurry Infiltration Freeze-Drying for Uniform Particle Distribution

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Solution Overview

Problem

Existing methods for distributing particulate material in ceramic matrix composites (CMCs) face challenges due to solvent and binder conversion to liquid states, leading to uneven distribution and clogging of pores, which results in non-uniform and potentially defective CMC materials.

Innovation Solution

A method involving freeze-drying and gelling techniques is employed to uniformly distribute particulate material, using thermally activated gels that maintain a solid phase during solvent removal, forming a structural support that prevents shrinkage and cracking, and ensuring even distribution of particulate material within the CMC.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional drying methods are used to remove solvent from slurry infiltrated preform, then solvent removal is achieved, but non-uniform distribution of particulate material occurs and pores become clogged

Engineering Contradiction:

Improvesolvent removalVSAvoiduniformity of particulate material distribution

Core Design Contradiction:

Loss of substanceVSManufacturing precision

Solution Approach 1:

The invention employs freeze-drying (lyophilization) which utilizes phase transition of water from liquid to solid (freezing) and then from solid to gas (sublimation). This phase transition approach removes solvent without passing through the liquid state that causes capillary action and non-uniform distribution, thereby resolving the contradiction between solvent removal and uniformity of particulate material distribution

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention changes the temperature parameter from conventional drying (heating) to freeze-drying (cooling below freezing point). This parameter change prevents the solvent from remaining in liquid state during removal, eliminating capillary action effects that cause non-uniform distribution and pore clogging, thus achieving both solvent removal and uniform particulate material distribution

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If liquid solvent and binder are used in slurry infiltration, then infiltration process is enabled, but capillary action causes liquid to move to fiber surfaces and create non-uniform distribution

Engineering Contradiction:

Improveinfiltration processVSAvoiduniformity of particulate material distribution

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention uses freeze-drying to transition the solvent from liquid to solid and then to gas phase, eliminating the liquid state that enables capillary action. This resolves the contradiction by allowing infiltration to proceed with liquid slurry while preventing the harmful capillary movement during the subsequent drying stage

Inventive Principle:

Principle #36Phase transitions

Solution Approach 2:

The invention converts the potential harm of liquid solvent movement into a benefit by using freeze-drying. The structured ice formation during freezing actually helps distribute particles uniformly, and the sublimation process removes solvent without causing capillary action, thus converting what would be a harmful liquid flow into a beneficial uniform distribution

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 achieves a more uniform and consistent distribution of particulate material, preventing blocking of infiltration paths and reducing defects in the CMC, thereby improving the material's structural integrity and properties.

Implementation Method 1

freezing the slurry infiltrated preform comprising the particulate material to form at least one frozen slurry infiltrated preform

Methodology Applied

Scientific EffectFreezing: Freezing

Implementation Method 2

sublimating the frozen slurry infiltrated preform comprising the particulate material to form at least one structural support comprising the particulate material uniformly distributed thereupon

Methodology Applied

Scientific EffectSublimation: Sublimation

Data Source

PatentUS20250388514A1Slurry Infiltration with Freeze Drying and Gelling for More Uniform Distribution of Particulate Material

Publication Date: 2025.12.25 RTX CORP

AI summary

A method for uniformly distributing particulate matter in a fiber reinforcement of a CMC material, comprising: providing at least one preform of at least one fiber reinforcement; infiltrating the preform with at least one slurry containing at least one particulate material and at least one solvent to form at least one slurry infiltrated preform comprising the particulate material; freezing the slurry infiltrated preform containing the particulate material to form at least one frozen slurry infiltrated preform containing the particulate material; sublimating the frozen slurry infiltrated preform including the particulate material to form at least one structural support comprising the particulate material uniformly distributed thereupon within at least one sublimated slurry infiltrated preform; and melt-infiltrating with at least one metal, at least one metalloid, at least one metal alloy, or at least one metalloid alloy, the sublimated slurry infiltrated preform containing the structural support to form a melt-infiltrated CMC material.