ALD Coatings for Refractory Stability in High-Temperature Steam

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Ceramic refractory materials, such as SiC and Si3N4, degrade in high temperature steam environments due to porosity in mullite-alumina coatings formed by CVD, allowing steam to oxidize and degrade the ceramic.

Innovation Solution

Utilize Atomic Layer Deposition (ALD) to create conformal, non-porous coatings of alumina and mullite on ceramic substrates, ensuring uniform bonding and controlled stoichiometry to enhance oxidation resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If CVD is used to form mullite-alumina coating, then coating can be formed on ceramic substrate, but the coating is porous allowing steam penetration and oxidation

Engineering Contradiction:

Improveoxidation resistanceVSAvoidsteam penetration through pores

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the deposition method from CVD to ALD, which fundamentally alters the coating formation parameters. ALD produces dense, non-porous coatings with controlled thickness and stoichiometry, eliminating the porosity problem inherent in CVD coatings while maintaining the protective function against steam and oxidation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite coating system with multiple functional layers: an ALD-formed dense mullite-alumina barrier layer to prevent steam penetration, and an outer silica scale layer for environmental resistance. This composite structure combines the advantages of both materials to achieve superior protection against oxidation and steam degradation

Inventive Principle:

Principle #40Composite materials

2Reliability

If coating thickness is increased to improve protection, then oxidation resistance improves, but coating complexity and deposition time increase

Engineering Contradiction:

Improveoxidation resistanceVSAvoidcoating structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the self-limiting nature of ALD deposition, where each cycle deposits a precisely controlled thickness (typically nanometer-scale) that is uniform and conformal. This allows achieving adequate protection with thin coatings (e.g., 1-10 micrometers) rather than thick coatings, simplifying the overall structure while maintaining effectiveness

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes from uncontrolled CVD deposition to precisely controlled ALD deposition, where coating thickness and composition are determined by the number of deposition cycles. This enables achieving optimal protection with minimal thickness, reducing complexity while improving reliability

Inventive Principle:

Principle #35Parameter changes

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

Achieves a 64% improvement in oxidation resistance of SiC, with films remaining intact after high temperature exposure, reducing degradation and maintaining structural integrity.

Implementation Method 1

The present invention relates, in part, to a discovery of a method for using atomic layer deposition (ALD) to improve the stability of refractory materials in high temperature steam

Methodology Applied

Scientific EffectAtomic Layer Deposition:

Implementation Method 2

the herein disclosed conformal films are configured to be used as an environmental barrier to protect the ceramic substrate from oxidation, for example, when exposed to high temperature steam

Methodology Applied

Scientific EffectOxidation resistance: Oxidation

Data Source

PatentUS12460295B2Stability of refractory materials in high temperature steam

Publication Date: 2025.11.04 THE REGENTS OF THE UNIVERSITY OF COLORADO

AI summary

The present invention relates, in part, to a discovery of a method for using atomic layer deposition (ALD) to improve the stability of refractory materials in high temperature steam, and compositions produced by the method.