Cold Spray Laminate Adhesion via Non-Metal Surface Activation
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Solution Overview
Problem
Existing cold spraying methods struggle to form films with high adhesion on substrates with high hardness due to insufficient anchor effect and peening powder remaining in the film.
Innovation Solution
A method involving a blasting step using non-metal powders like ceramics or glass to roughen the substrate surface, followed by a film forming step using metal or alloy powders, both in a solid phase state at elevated gas pressures, to enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cold spraying method is used to form a metal film on a high hardness substrate, then oxidation is suppressed and phase transformation is avoided, but the anchor effect is insufficient and adhesion strength is low
Solution Approach 1:
The invention applies a preliminary surface treatment step before film formation, where powder material is sprayed onto the substrate at lower gas pressure (0.1 to 1 MPa) to activate and roughen the substrate surface. This preliminary action creates anchor points that will later enhance the adhesion of the metal film formed at higher pressure, directly resolving the contradiction between maintaining cold spraying benefits and achieving sufficient anchor effect.
Solution Approach 2:
The invention changes the gas pressure parameter between two distinct stages: lower pressure (0.1 to 1 MPa) for surface activation and higher pressure for film formation. This parameter variation allows the same cold spraying process to perform different functions at different stages, enabling both substrate activation and high-quality film deposition without compromising the anchor effect.
2Reliability
If peening powder is mixed with film raw material powder to roughen substrate surface, then surface activation is achieved, but peening powder remains in the film and prevents formation of pure film
Solution Approach 1:
The invention segments the powder spraying process into two distinct stages: first spraying only powder material for surface activation, then spraying film raw material powder for film formation. This segmentation prevents contamination of the film with activation powder, ensuring film purity while still achieving the desired surface roughening effect in the first stage.
Solution Approach 2:
The surface activation using powder material is performed as a preliminary step before the actual film formation. This preliminary action prepares the substrate surface with adequate roughness and anchor points, and since it is completed before film deposition, the subsequent film layer can be formed purely from film raw material without contamination.
3Reliability
If powder speed is reduced for surface activation, then substrate surface is activated, but high hardness substrate cannot sufficiently obtain anchor effect
Solution Approach 1:
The invention optimizes the gas pressure parameter for surface activation on high hardness substrates, using a range of 0.1 to 1 MPa which provides sufficient kinetic energy to activate and roughen hard surfaces while preventing excessive deformation. This parameter optimization enables the anchor effect to be achieved on high hardness substrates that would not respond adequately to lower pressure treatments.
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 effectively anchors the film to the substrate, removing oxide films and improving interfacial strength, resulting in a laminate with excellent adhesion.
Implementation Method 1
a gas heated to a temperature lower than a melting point of the metal or the alloy
Implementation Method 2
a tapering divergent (de Laval) nozzle together with an inert gas heated to a temperature of the melting point or the softening point of the material powder or lower
Implementation Method 3
when a material powder of the metal film collides with the substrate, plastic deformation occurs between the powder and the substrate, and an anchor effect that the powder and the substrate enter each other to be bonded to each other is obtained
Implementation Method 4
oxide films thereof are broken, and metal bonding occurs by newly formed surfaces
Implementation Method 5
a cold spraying method for spraying a material powder onto a substrate at a high temperature and a high speed and thereby depositing and coating the material powder on the substrate
Data Source
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AI summary
By spraying powder of non-metal onto a surface of a substrate having a high hardness by a cold spraying method to blast the surface of the substrate and then forming a film by the cold spraying method, a laminate having excellent adhesion between the substrate and the film and a method for manufacturing the laminate are provided. A laminate 1 includes a substrate 10 made of a metal or an alloy having a Vickers hardness of 120 HV or more and having irregularities on a surface thereof, and a film 11 formed on a surface of the substrate 10 and made of a metal or an alloy. The film 11 forms metal bonding with the substrate 10.