Hybrid Deposition for Dense Composite Matrix
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Solution Overview
Problem
Current deposition methods for composite materials, such as silicon carbide (SiC)-SiC, face limitations including high temperature requirements, large open porosities, and inability to fill porosities distal from the surface due to uncontrolled deposition rates and line-of-sight deposition characteristics, which restrict substrate materials and geometry.
Innovation Solution
A hybrid deposition technique involving a first coating method, such as electrophoretic deposition or chemical vapor infiltration, followed by atomic layer deposition (ALD) to form a composite matrix, which infiltrates submicron porosities and provides a dense, uniform coating without the need for high-temperature annealing or sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature annealing or sintering is used to form composite matrix, then deposition speed is improved, but substrate material selection is limited and substrate integrity may be compromised
Solution Approach 1:
The patent changes the temperature parameter from high temperature (1000°C+) to low temperature (<400°C) processing by using plasma-enhanced chemical vapor deposition (PECVD) instead of conventional thermal CVD or sintering. This parameter change enables deposition on temperature-sensitive substrates while maintaining acceptable deposition rates through plasma activation
Solution Approach 2:
The patent replaces the thermal field (heat-based sintering/annealing) with a plasma field (electromagnetic field) to enable low-temperature deposition. The plasma provides the necessary activation energy without requiring high temperatures, thus protecting substrate integrity while forming the composite matrix
2Productivity
If conventional deposition methods are used, then deposition rate is high, but porosity control is poor and open porosities remain
Solution Approach 1:
The patent uses multiple sequential PECVD cycles to deposit different layers (e.g., SiC layer, SiO2 layer, another SiC layer) that progressively fill and seal porosities. This continuous deposition process ensures complete pore closure while maintaining high overall deposition rates, achieving both productivity and porosity control
Solution Approach 2:
The patent creates a composite matrix structure by depositing alternating layers of different materials (e.g., SiC and SiO2) that work together to fill and seal porosities. The composite structure provides both rapid deposition capability and excellent porosity control through the synergistic effect of different material properties
3Device complexity
If line of sight deposition is used, then deposition process is simple, but porosities distal from surface cannot be filled
Solution Approach 1:
The patent employs periodic plasma activation and precursor exposure cycles that enable conformal deposition on complex geometries. The plasma periodically activates the substrate surface and deposited layers, allowing reactants to penetrate deep into porosities and achieve uniform coating throughout the substrate structure, not just on accessible surfaces
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 method allows for the formation of a dense, nonporous composite matrix with improved mechanical properties and corrosion resistance, capable of infiltrating varying pore sizes from microns to millimeters, while maintaining substrate integrity and avoiding extreme temperature exposure.
Implementation Method 1
subjecting the non-porous metal or ceramic substrate to electrophoretic deposition (ECD) to apply a first coating including first ceramic or metallic particles
Implementation Method 2
subjecting the coated substrate to atomic layer deposition to apply a second coating including second ceramic or metallic particles and thereby form the composite matrix
Implementation Method 3
Composites such as silicon carbide (SiC)-SiC are typically prepared by infiltration of mesh material/wires with Chemical Vapor Infiltration (CVI) at temperatures above 1000° C.
Data Source
AI summary
Provided herein are methods of forming a composite matrix on a porous substrate or a non-porous substrate, the methods including subjecting the substrate to a first deposition method to apply a first coating including first ceramic or metallic particles and form a coated substrate and subjecting the coated substrate to atomic layer deposition to apply a second coating and form the composite matrix, wherein the second coating includes second ceramic or metallic particles.