Thermal Spray Coating on Organic Substrates
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Solution Overview
Problem
High-temperature thermal spraying has been considered unsuitable for coating organic materials due to the risk of melting or degassing, limiting the application of high melting point materials on surfaces containing inorganic materials.
Innovation Solution
A method involving a thermal sprayed first layer of metal coating material less than 200 micrometres in thickness, followed by a further layer of higher melting point material, applied at a low deposition rate to minimize heat transfer and prevent damage to the substrate, allowing for the successful coating of organic material surfaces with materials like carbon fibre composites.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If thermal spraying is applied to organic material surfaces, then high melting point materials can be deposited, but the organic substrate melts or degrades due to high temperature
Solution Approach 1:
The coating process is divided into multiple sequential layers: a first layer of coating material (metal or ceramic) is applied to the organic substrate, followed by a second layer of high melting point material. This segmentation allows the substrate to be exposed to lower temperatures during the critical initial deposition phase, preventing degradation while still enabling subsequent high-temperature material deposition.
Solution Approach 2:
The first layer of coating material is deposited onto the organic substrate before applying the high melting point material. This preliminary layer acts as a thermal barrier and protective interface, preparing the substrate to withstand subsequent high-temperature exposure without direct contact with the hot plasma or spray material.
2Strength
If thermal spraying is used to deposit coating material, then a protective layer is formed, but the high temperature damages the organic substrate through melting or degassing
Solution Approach 1:
The first layer of coating material serves as an intermediary layer between the organic substrate and the high melting point coating material. This intermediate layer absorbs and distributes thermal energy, protecting the organic substrate from direct thermal exposure while still allowing the high melting point material to be successfully deposited on top.
Solution Approach 2:
The invention creates a composite structure consisting of an organic substrate, a first layer of coating material (metal or ceramic), and a second layer of high melting point material. This multi-material composite approach combines the advantages of each material while mitigating their individual disadvantages, particularly the thermal sensitivity of organic materials.
3Temperature
If a thick layer of high melting point material is applied, then thermal protection is enhanced, but heat transfer to the organic substrate increases causing damage
Solution Approach 1:
The coating structure is designed with different layers having different local properties: the first layer is optimized for adhesion to the organic substrate and initial thermal protection, while the second layer provides enhanced thermal barrier capability. Each layer's thickness and material composition are tailored to its specific function, creating a gradient of protective qualities.
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
Enables the application of high melting point materials on organic surfaces without deleterious melting or degassing, providing enhanced mechanical, thermal, and electrical properties while minimizing substrate damage, resulting in lightweight and strong coated articles.
Implementation Method 1
In plasma spraying, the material to be deposited is melted and propelled towards the substrate to be coated. The plasma jet temperature may be of the order of 20,000 K.
Implementation Method 2
A low deposition rate minimises heat transfer to the substrate, thus minimising risk of damage to the substrate.
Data Source
AI summary
An article, at least a surface of the article being made of or containing an organic material, and a thermally sprayed layer of coating material on the surface.