Physical Vapor Deposition Coating for Composite Lightning Protection

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Solution Overview

Problem

Existing methods for increasing the electrical conductivity of composite parts, such as those used in aeronautic, naval, and wind turbine applications, are hindered by weight addition and high costs due to the use of metallic meshes or foils, and current vapor deposition methods are not fully efficient in reducing weight while maintaining conductivity.

Innovation Solution

A method involving physical vapor deposition of a metal coating layer, typically 0.1-10 µm thick, applied in vacuum conditions using techniques like cathodic arc deposition, magnetron sputtering, or thermal evaporation, with surface preparation steps including ion beam modification and intermediate bonding layers to enhance adherence and conductivity, specifically targeting composite parts for lightning strike protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic mesh or foil is used to increase electrical conductivity of composite part surface, then electrical conductivity is improved, but weight of the composite part increases significantly

Engineering Contradiction:
Improveelectrical conductivityVSAvoidweight of composite part
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical system of metallic mesh or foil with a vapor deposition process that applies metal atoms directly to the composite surface. This substitution eliminates the need for physical mesh structures while achieving the same electrical conductivity function through a thin conformal coating layer.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the parameter of coating thickness from the millimeter scale (mesh/foil) to the micrometer/nanometer scale (vapor deposition coating). This parameter change reduces the amount of metal material required by several orders of magnitude, thereby dramatically reducing weight while maintaining electrical conductivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If metallic mesh or foil is used to increase electrical conductivity, then conductivity is improved, but manufacturing cost increases due to manual operations

Engineering Contradiction:
Improveelectrical conductivityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces manual mechanical operations of mesh application with an automated vapor deposition process. This substitution eliminates labor-intensive manual work while providing consistent, controllable coating application, thereby reducing manufacturing costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The vapor deposition process is self-regulating and automatically forms a uniform coating layer on the composite surface without requiring manual intervention. The process inherently controls coating thickness and coverage, eliminating the need for skilled manual operations.

Inventive Principle:
Principle #25Self-service

3Reliability

If thick metal layers are applied to ensure conductivity, then electrical conductivity is improved, but weight and surface finish quality deteriorate

Engineering Contradiction:
Improveelectrical conductivityVSAvoidsurface finish
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The patent changes the coating thickness parameter to the micrometer/nanometer range through vapor deposition, which is thin enough to preserve surface finish quality and aerodynamic properties while still providing sufficient electrical conductivity for lightning strike protection.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a thin film coating approach where a ultra-thin metal layer conformally coats the composite surface. This thin film is sufficiently conductive for electrical protection while being thin enough to maintain the original surface geometry and finish quality.

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

This method results in composite parts with improved electrical conductivity and reduced weight, enabling effective lightning strike protection without excessive weight addition, and allows for automation and cost reduction by eliminating the need for additional components like metallic meshes.

Implementation Method 1

applying a coating layer comprising a metal, the coating layer thickness being 0.1-10 μm and said coating layer being applied on the at least one surface of the composite part, by means of physical vapour deposition; wherein the application of the coating layer is made in vacuum conditions

Methodology Applied
Scientific EffectPhysical vapor deposition: Physical Vapour Deposition

Implementation Method 2

the step of preparing the surface of the composite part comprises ion beam modification of the surface using at least one gas

Methodology Applied
Scientific EffectIon beam modification: Ion Beam

Implementation Method 3

Cathodic arc deposition: an electrical arc literally blasts ions from the cathode of the coating material. The arc has an extremely high power density resulting in a high level of ionization (30-100%), multiply charged ions, neutral particles, clusters and macro-particles (droplets).

Methodology Applied
Scientific EffectCathodic arc deposition: Cathodic Arc Deposition

Implementation Method 4

Magnetron sputtering: the coating material is placed in a target and is knocked by a plasma, usually a noble gas such as argon, to pull out a few atoms of this material at a time.

Methodology Applied
Scientific EffectMagnetron sputtering: Sputtering

Implementation Method 5

Thermal evaporation: the coating material contained in a target or crucible is brought to the evaporation or sublimation temperature, by means of a resistive heater or by a high energy electron beam directed towards the coating layer.

Methodology Applied
Scientific EffectThermal evaporation: Evaporation

Data Source

PatentEP3249072B1Method for increasing the electrical conductivity of a composite part surface
Publication Date: 2019.07.31 AIRBUS DEFENCE & SPACE SAU
  • EP3249072B1 patent drawingFigure 1~2
  • EP3249072B1 patent drawingFigure 3~4
  • EP3249072B1 patent drawingFigure 5~6

AI summary

This invention is related to a method for treating a composite part comprising at least one surface, the method comprising the step of applying a coating layer of 0.1-10 µm thick on a surface of the composite part, by means of physical vapour deposition. The invention also refers to a composite part treated by such a method.