DLC-Coated Solid Fuel Pellets for Oxidation-Resistant Encapsulation

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Solution Overview

Problem

Existing polymer coatings for red phosphorus and other solid fuels are hazardous, lead to environmental degradation, and result in costly waste disposal, while also compromising the thermodynamic properties and burn rates of the fuels.

Innovation Solution

The application of a thin, conformal DLC coating using near-vacuum plasma deposition processes, which encapsulates the solid fuels, providing protection against oxidative, reductive, hydrolytic, and other damage, and improving free-flow characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polymer coatings are applied to encapsulate red phosphorus, then protection against degradation is improved, but thermodynamic properties and burn rates are worsened

Engineering Contradiction:

Improveprotection against degradationVSAvoidburn rate

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the material parameter from organic polymer to inorganic DLC coating, and controls coating thickness parameter to maintain thermodynamic properties while providing protection

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure with DLC coating layer over red phosphorus core, combining the protective properties of DLC with the energetic properties of red phosphorus

Inventive Principle:

Principle #40Composite materials

2Reliability

If polymer coatings are applied to red phosphorus, then encapsulation is improved, but hazardous waste streams and disposal costs are worsened

Engineering Contradiction:

ImproveencapsulationVSAvoidhazardous waste

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameter from organic polymer to inorganic DLC coating, eliminating carbon-based waste and associated environmental hazards

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The DLC coating provides durable protection without creating long-term waste management issues, effectively replacing disposable polymer coatings with a more sustainable solution

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If polymer coatings are applied to solid fuels, then protection is improved, but uniformity and low-defect density are worsened

Engineering Contradiction:

ImproveprotectionVSAvoiduniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical/chemical polymer coating processes with plasma-based DLC deposition, providing more uniform and controllable coating application

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent controls plasma process parameters to achieve uniform coating thickness and low defect density that cannot be achieved with polymer coating methods

Inventive Principle:

Principle #35Parameter changes

4Reliability

If organic polymers are used to encapsulate red phosphorus, then protection against degradation is improved, but weight and bulk are worsened

Engineering Contradiction:

Improveprotection against degradationVSAvoidweight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material density parameter by using DLC coating which provides equivalent or superior protection with reduced mass compared to polymer coatings

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The DLC coating forms a thin film encapsulation that provides protection with minimal added weight, unlike bulkier polymer coatings

Inventive Principle:

Principle #30Flexible shells and thin films

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 DLC coating process eliminates hazardous waste streams, reduces health risks, and decreases disposal costs, while achieving a near-continuous, even, and low-defect coating on comminuted materials.

Implementation Method 1

The embodiments herein have successfully demonstrated the application of one or more of diamond-like carbon (DLC), graphitic carbon, amorphous or tetrahedral carbon, hydrogenated or non-hydrogenated carbon, and other sp2 and sp3 hybridized carbon existing in metastable phases to apply a thin, conformal coating

Methodology Applied

Scientific EffectPlasma deposition: Physical Vapour Deposition

Implementation Method 2

through the use of near-vacuum plasma deposition processes

Methodology Applied

Scientific EffectPlasma: Plasma

Data Source

PatentUS12264289B1Apparatus and method for plasma coating solid fuels and coated solid fuels produced using same

Publication Date: 2025.04.01 THE GOVERNMENT OF THE UNITED STATES OF AMERICA AS REPRESENTED BY THE SECRETARY DEPARTMENT OF HEALTH & HUMAN SERVICES

AI summary

Solid fuel pellets or particles are coated with a diamond-like and/or graphitic coating to impart increased resistance to oxidation or other forms of degradation. An apparatus and method for producing solid fuel pellets or particles or other comminuted or particulate material that are coated with diamond-like and/or graphitic coatings employ plasma coating of the particles or comminuted material in a plasma chamber that has provision for agitating and/or stirring the particles during the plasma coating process. The gas feed to the plasma chamber may contain at least one organic carbon source.