Cold Spray Laminate With Soft Intermediate Layer

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Solution Overview

Problem

The existing cold spray methods do not effectively achieve high adhesion strength between a metal substrate and the metal film, as they lack a clear relationship between substrate heating and adhesion strength, and do not provide a method to enhance the bonding between the substrate and the metal film.

Innovation Solution

A lamination process involving a metal substrate with a softer intermediate layer formed by sputtering, where metal powder is sprayed with a heated gas at high velocity to maintain a solid phase, breaking through the intermediate layer and forming metallic bonds with the substrate, thereby achieving high adhesion strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If material powder is sprayed onto a substrate using conventional cold spray method, then a metal film is formed on the substrate, but the adhesion strength between the metal film and substrate is insufficient

Engineering Contradiction:
Improveadhesion strengthVSAvoidbonding quality
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

An intermediate layer made of a metal different from both the substrate and film material is introduced between the substrate and the metal film. This intermediate layer serves as a mediator that improves adhesion strength by creating a gradient transition in material properties, preventing direct contact between incompatible materials and reducing interfacial stress concentration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The structure is designed as a composite system consisting of three distinct material layers (substrate, intermediate layer, and film) with different physical and mechanical properties. This composite structure allows optimization of each layer's characteristics to achieve overall superior adhesion strength compared to direct coating.

Inventive Principle:
Principle #40Composite materials

2Strength

If substrate heating is applied to improve adhesion, then adhesion efficiency increases, but the optimal temperature range and its effect on adhesion strength are not clearly established

Engineering Contradiction:
Improveadhesion strengthVSAvoidtemperature control precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The substrate temperature is controlled within a specific range of 100°C to 500°C before and during powder spraying. This parameter optimization ensures that the substrate is warm enough to improve powder adhesion and promote diffusion bonding, but not so hot as to cause premature melting or oxidation, thereby achieving reliable adhesion strength.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The substrate is pre-heated to the optimal temperature range before the powder spraying process begins. This preliminary heating action prepares the substrate surface to enhance powder adhesion from the start of deposition, ensuring consistent bonding quality throughout the film formation process.

Inventive Principle:
Principle #10Preliminary action

3Strength

If an intermediate layer is formed by sputtering to improve adhesion, then bonding strength increases, but the thickness of the intermediate layer must be precisely controlled

Engineering Contradiction:
Improvebonding strengthVSAvoidintermediate layer thickness
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The intermediate layer thickness is controlled within the range of 1 nm to 100 nm. This precise thickness control ensures that the layer is thin enough to maintain strong interfacial bonding and allow diffusion across the interface, while being thick enough to provide sufficient adhesion improvement and cover surface irregularities.

Inventive Principle:
Principle #35Parameter changes

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 process results in a lamination with improved adhesion strength between the metal substrate and film, as demonstrated by increased tensile strength and reduced peeling at the boundary surface, even when the substrate is heated during film deposition.

Implementation Method 1

an intermediate layer formed on a surface of the substrate by sputtering and formed of a metal or alloy that is softer than the substrate

Methodology Applied
Scientific EffectSputtering: Sputtering

Implementation Method 2

a metal film deposited on a surface of the intermediate layer by accelerating a powder material of a metal or alloy together with a gas heated to a temperature lower than a melting point of the powder material and spraying the powder material onto the intermediate layer while keeping the powder material in a solid phase

Methodology Applied
Scientific EffectCold spray:

Data Source

PatentEP2695972B1Laminate, and method for producing laminate
Publication Date: 2019.06.05 NHK SPRING CO LTD
  • EP2695972B1 patent drawingFigure 1~2
  • EP2695972B1 patent drawingFigure 3~4
  • EP2695972B1 patent drawingFigure 5

AI summary

Provided is a method for manufacturing a lamination, in manufacturing a lamination in which a metal film is formed on a substrate using the cold spray method, having high adhesion strength between the substrate and the metal film. A lamination 10 according to the present invention includes a substrate 1 formed of a metal or alloy, an intermediate layer 2 formed on a surface of the substrate and is formed of a metal or alloy that is softer than the substrate 1, and a metal film 3 deposited by accelerating a powder material of a metal or alloy together with a gas heated to a temperature lower than the melting point of the powder material and spraying it onto the intermediate layer 2 while keeping it in a solid phase.