Cold-Sprayed Nickel Coating for Oxide-Resistant Brazed Joints
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Solution Overview
Problem
Existing brazing methods for metal components face challenges due to the formation of oxide films on metal surfaces during heating, which hinder the formation of effective braze joints, and chemical bath processes generate waste and require extensive surface preparation and masking.
Innovation Solution
A cold-spray method is used to deposit a nickel-containing coating on the braze region of metal components, preventing oxide formation and allowing for a more uniform and thicker coating without the need for special cleaning or surface treatment, followed by brazing to form a strong joint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If chemical bath process is used to deposit coating on braze region, then coating can be formed, but waste is generated and extensive surface preparation and masking are required
Solution Approach 1:
The patent replaces the chemical bath process (chemical system) with a cold spray process (mechanical/physical system) that uses high-velocity particles to deposit coating material. This substitution eliminates the need for chemical baths, reducing waste generation while simplifying the manufacturing process by removing extensive surface preparation and masking requirements.
Solution Approach 2:
The patent changes the deposition parameters from chemical immersion (chemical bath) to high-velocity particle impact (cold spray). This parameter change allows coating to be deposited without extensive surface preparation, as the cold spray process can accommodate various surface conditions while reducing waste and eliminating masking needs.
2Reliability
If brazing is performed without protective coating, then process is simple, but oxide films form on metal surfaces that negatively impact braze joint formation
Solution Approach 1:
The patent applies protective coating to the braze region before the brazing operation. This preliminary action prevents oxide film formation on the metal surfaces during heating, ensuring reliable braze joint formation. The cold spray coating is applied in advance, creating a protective barrier that eliminates oxidation concerns during subsequent brazing.
Solution Approach 2:
The patent introduces a nickel-based protective coating as an intermediary layer between the metal components and the oxidizing atmosphere during brazing. This intermediary coating prevents direct oxidation of the base metal surfaces, ensuring clean metallurgical bonding occurs during the brazing process while allowing the brazing operation itself to remain relatively simple.
3Manufacturing precision
If cold-spray method is used to deposit nickel-containing coating, then uniform coating on complex geometries is achieved and waste is reduced, but equipment complexity increases
Solution Approach 1:
The patent segments the coating application process into a controlled cold spray deposition system that can be precisely directed at complex geometries. The cold-spray apparatus delivers particles in a controlled manner, allowing uniform coating thickness on intricate shapes by adjusting spray angles, distances, and particle velocities for different surface areas.
Solution Approach 2:
The patent utilizes parameter changes in the cold spray process (particle velocity, temperature, gas pressure, spray angle) to achieve uniform coating deposition on complex geometries. By dynamically adjusting these parameters during the spraying process, the system compensates for geometric variations and maintains consistent coating quality across different surface configurations.
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 cold-spray method reduces waste, achieves uniform coatings on complex geometries, and allows for a wider range of coating thicknesses, resulting in a strong, effective braze joint with enhanced tensile strength and reduced environmental impact.
Implementation Method 1
operating a cold-spray apparatus to deposit a feedstock comprising nickel-based alloy particles on a braze region of a first metallic component to form a nickel-containing coating on the braze region
Implementation Method 2
brazing the first metallic component and a second metallic component by exposing the braze region to a braze material to form a braze joint that bonds the first metallic component to the second metallic component
Data Source
AI summary
A method for joining two or more metallic components. The method includes operating a cold-spray apparatus to deposit a feedstock comprising nickel-based alloy particles on a braze region of a first metallic component to form a nickel-containing coating on the braze region. The method also includes brazing the first metallic component and a second metallic component by exposing the braze region to a braze material to form a braze joint that bonds the first metallic component to the second metallic component.