Induction Heating Cold Spray Coating Porosity
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Solution Overview
Problem
The cold spraying of Inconel alloys, such as IN718, is challenging due to high critical velocities and nozzle clogging, resulting in porous coatings, and traditional heat treatment methods are inefficient and unsuitable for complex components.
Innovation Solution
A method combining cold spray technology with induction heating to enhance the bonding strength and reduce porosity of coatings by applying a high-frequency alternating current to the coating as it is deposited, allowing for localized and efficient heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If cold spray is used to deposit Inconel coatings, then coating deposition is achieved, but nozzle clogging and high critical velocities occur resulting in porous coatings
Solution Approach 1:
The patent applies preliminary heating of the Inconel powder particles before they enter the cold spray nozzle. This preheating action modifies the particle properties to reduce clogging tendencies and improve flow characteristics through the nozzle, thereby preventing nozzle clogging and enabling better coating deposition with reduced porosity.
Solution Approach 2:
The patent changes the temperature parameter of the powder particles by heating them to specific ranges (e.g., 200-500°C) before deposition. This parameter change affects particle mobility, bonding characteristics, and flow behavior, which collectively reduce porosity in the coating and prevent nozzle clogging during the cold spray process.
2Manufacturing precision
If traditional furnace heat treatment is used to treat cold sprayed coatings, then heat treatment is achieved, but processing time is excessive and entire component must be treated
Solution Approach 1:
The patent replaces the traditional furnace heat treatment system with an induction heating system. This substitution uses electromagnetic induction to generate heat directly in the coating material, eliminating the need for lengthy furnace heating cycles and enabling localized, rapid heat treatment of the coating without treating the entire component.
Solution Approach 2:
The induction heating system provides localized heat treatment to the coating area only, rather than heating the entire component. This local quality approach concentrates thermal energy where needed to improve coating bonding strength while minimizing processing time and energy consumption compared to full-component furnace treatment.
3Productivity
If high particle velocities are used for cold spray, then deposition rate increases, but surface erosion and reduced coating quality occur
Solution Approach 1:
The patent applies preliminary heating to the powder particles before deposition, which modifies their impact characteristics. This preheating action allows the particles to maintain higher velocities for improved deposition rate while preventing excessive surface erosion and coating defects, as the heated particles exhibit better bonding behavior upon impact.
Solution Approach 2:
The patent changes the temperature parameter of the powder particles to optimize the balance between deposition rate and coating quality. By controlling the particle temperature within specific ranges, the system achieves high deposition rates through rapid cooling upon impact while maintaining coating integrity and minimizing surface erosion.
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 approach results in coatings with significantly reduced porosity and improved adhesion to the substrate, achieving better structural properties compared to traditional furnace heat treatment, with porosity levels as low as 0.2% and enhanced cohesive strength.
Implementation Method 1
The coating is heated by induction heating
Implementation Method 2
a method of spray coating a substrate... comprising: forming a vacuum... spraying coat metal particles... induction heating the coating
Data Source
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AI summary
A method of spray coating a substrate is disclosed, the method comprising: a step (71) of spray coating metal particles onto a substrate (55); and a step (81) of induction heating the coating (56); wherein the step of induction heating comprises performing the induction heating in a vacuum.