Dual-Layer SiOxCy Coating for Aircraft Window Durability

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Solution Overview

Problem

Current transparent polymer coatings for applications like aircraft windows lack durability, UV protection, and resistance to chemicals and thermal stresses, requiring a hard yet flexible coating that can withstand operational flexing and thermal changes while maintaining optical quality.

Innovation Solution

A dual-layer coating system comprising a UV blocking layer and a hard SiOxCy layer, applied using plasma deposition, which provides enhanced durability, UV protection, and chemical resistance, with the hard layer having a composition of 30-35% Si, 25-30% C, and 40-45% O, and the soft layer ensuring adhesion and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a single hard coating layer is applied to provide abrasion resistance, then wear durability is improved, but the coating becomes brittle and cannot withstand thermal stresses and operational flexing

Engineering Contradiction:
Improveabrasion resistanceVSAvoidresistance to thermal stresses and flexing
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The coating system is divided into two distinct layers: a soft undercoat layer that provides flexibility and adhesion, and a hard topcoat layer that provides abrasion resistance. This segmentation allows each layer to perform its specific function without compromising the other, resolving the contradiction between hardness and flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite coating structure combining two materials with different properties - a soft polymer-based undercoat and a hard inorganic-based topcoat. This composite approach allows the coating system to exhibit both flexibility (from the soft layer) and abrasion resistance (from the hard layer), eliminating the need to choose between conflicting properties.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If polymer based transparency materials are used to reduce weight, then weight is reduced, but the materials become soft and susceptible to UV, chemical attack and mechanical degradation

Engineering Contradiction:
Improveweight of transparencyVSAvoidresistance to UV and chemical attack
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The invention applies a composite coating system on polymer transparency materials where the hard topcoat layer provides UV and chemical resistance while the soft undercoat maintains adhesion. This allows the lightweight polymer substrate to gain the durability properties of harder materials without adding significant weight.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The soft undercoat layer acts as an intermediary between the polymer substrate and the hard topcoat layer, providing both adhesion to the substrate and a transition zone that helps manage stress, while the hard topcoat provides the necessary UV and chemical protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If glass is used to provide abrasion resistance and strength, then durability is improved, but the material becomes much heavier and more expensive

Engineering Contradiction:
Improveabrasion resistanceVSAvoidweight of transparency
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The invention creates a composite structure where a thin hard topcoat layer provides glass-like abrasion resistance, while the underlying polymer substrate maintains the lightweight advantage. This composite approach allows the system to achieve glass-level durability without the weight penalty of using solid glass.

Inventive Principle:
Principle #40Composite materials

4Duration of action of stationary object

If the hard coating layer is made thicker to improve abrasion resistance, then wear durability is improved, but the coating becomes more brittle and less flexible

Engineering Contradiction:
Improvewear durabilityVSAvoidflexibility
Core Design Contradiction:
Duration of action of stationary objectVSAdaptability or versatility

Solution Approach 1:

The coating is segmented into two layers with the hard topcoat optimized for abrasion resistance and the soft undercoat optimized for flexibility. This segmentation allows the hard layer to be sufficiently thick for durability without compromising overall flexibility, as the soft undercoat compensates for brittleness.

Inventive Principle:
Principle #1Segmentation

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 coating significantly improves the lifespan of transparent substrates by offering superior UV protection, chemical resistance, and abrasion resistance, maintaining optical clarity and flexibility, and can be seamlessly varied in thickness for different applications.

Implementation Method 1

A dual-layer coating system comprising a UV blocking layer and a hard SiOxCy layer, applied using plasma deposition

Methodology Applied
Scientific EffectPlasma deposition: Plasma Enhanced Chemical Vapour Deposition

Implementation Method 2

a UV blocking layer... blocks greater than about 97% of UV radiation up to 375 nm

Methodology Applied
Scientific EffectUV blocking: Absorption (EM radiation)

Data Source

PatentEP3444306B1Durable UV blocking transparent coating
Publication Date: 2020.10.21 THE BOEING CO
  • EP3444306B1 patent drawingFigure 1~2
  • EP3444306B1 patent drawingFigure 3~4

AI summary

A coating and associated method for coating is disclosed. The coating provides a hard, transparent, UV blocking coating for a substrate. A UV blocking layer is first deposited upon the substrate, and a hard coating is deposited above the UV blocking layer. A soft coating layer may be deposited between the UV blocking layer and the hard coating. The soft and hard coating layers may both have the general composition SiOxCy. The soft and hard coating layers may be deposited by a plasma vapor deposition process.