Ceramic Composite Coating for Stray Light Absorption

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Solution Overview

Problem

Current black coatings for optical and thermal applications do not achieve optimal stray light absorption and Lambertian reflectance, particularly in space-borne instruments, and lack compatibility with various substrates and environmental conditions.

Innovation Solution

A ceramic composite coating comprising a metal oxide matrix with embedded metastable carbide nanoparticles that decay into metal-carbon composite nanoparticles, fabricated using chemical vapor deposition, offering high absorptance and tunable optical properties suitable for superblack coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional black coatings (paints, anodizations, plasma sprayed coatings) are used, then black surface appearance is achieved, but optimal stray light absorption and Lambertian reflectance are not achieved

Engineering Contradiction:

Improveblack surface appearanceVSAvoidstray light absorption performance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses a composite material consisting of a ceramic matrix (e.g., alumina, silica, zirconia) embedded with metal carbide nanoparticles (e.g., tungsten carbide, molybdenum carbide). This composite structure achieves both the black surface appearance and superior stray light absorption performance, resolving the contradiction between ease of manufacture and reliability of optical performance.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent controls the size, concentration, and distribution parameters of the metal carbide nanoparticles within the ceramic matrix. By optimizing these parameters, the coating achieves optimal light absorption and Lambertian reflectance while maintaining manufacturability through controlled deposition processes.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If advanced black coatings (Vantablack, Nano Black) are used, then very low reflectance is achieved, but compatibility with various substrates and environmental conditions is limited

Engineering Contradiction:

Improvereflectance performanceVSAvoidsubstrate compatibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The ceramic matrix-based coating system is designed to be universally applicable to multiple substrate types including metals, ceramics, and polymers. The coating process and material composition can be adjusted to accommodate different substrates and environmental conditions (space vacuum, thermal cycling, radiation), achieving both high reflectance performance and broad adaptability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent allows for local optimization of the coating properties by adjusting the nanoparticle concentration and distribution in different regions or for different substrate types. This enables the same base coating system to be adapted to specific local requirements of different substrates and application environments.

Inventive Principle:

Principle #3Local quality

3Reliability

If metastable carbide nanoparticles are embedded in ceramic matrix, then high absorptance and tunable optical properties are achieved, but manufacturing complexity increases

Engineering Contradiction:

Improveoptical propertiesVSAvoidmanufacturing process

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical manufacturing processes with chemical vapor deposition (CVD) methods. The metal carbide nanoparticles are formed in situ within the ceramic matrix through controlled chemical reactions during deposition, eliminating the need for separate nanoparticle synthesis, mixing, and application steps. This chemical approach simplifies the overall manufacturing process while maintaining the complex nanoparticle structure required for optimal optical properties.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 ceramic composite coating achieves low total hemispherical reflectivity, is compatible with diverse substrates, and withstands intense radiation, making it suitable for space and high-vacuum applications while minimizing outgassing and particulate contamination.

Implementation Method 1

The ceramic composite coating achieves low total hemispherical reflectivity... When light strikes the layer of CNTs, instead of bouncing off it is trapped between the tubes before eventually becoming heat

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Implementation Method 2

comprising a ceramic matrix, which is not a carbide matrix, having embedded therein carbide nanoparticles... the carbide nanoparticles (in particular metal carbide nanoparticles) and/or metal-carbon composite nanoparticles

Methodology Applied

Scientific EffectPhase transition: Phase Change

Implementation Method 3

fabricated using chemical vapor deposition

Methodology Applied

Scientific EffectChemical vapor deposition: Chemical Vapour Deposition

Data Source

PatentUS10710935B2Ceramic composite and production method thereof

Publication Date: 2020.07.14 LUXEMBOURG INSTITUTE OF SCIENCE AND TECHNOLOGY (LIST)

AI summary

A black ceramic composite coating is presented. The ceramic composite coating comprises a ceramic matrix having embedded therein carbide nanoparticles (in particular metal carbide nanoparticles) and/or metal-carbon composite nanoparticles (with separate metal and carbon phases) embedded therein. The carbide nanoparticles are metastable and the metal-carbon composite nanoparticles are decay products of the metastable carbide nanoparticles. A further aspect of the invention relates to producing such a ceramic composite coating.