Transient Liquid Phase Bonding for Metal-Plated Polymer Joints

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Solution Overview

Problem

Conventional methods for joining metal-coated non-metallic materials, such as polymers and composites, are inadequate as they often deform or destroy the polymer or composite substrate due to high temperatures required for welding or brazing, and existing fastening methods like bolts and rivets have limitations, while current metallic coating application methods fail to provide a robust and thermally stable bond with customized properties.

Innovation Solution

A method involving transient liquid phase (TLP) bonding, where an interlayer composed of elements like gallium, indium, or selenium is used between a metallic component and a metal-plated non-metallic component, heated to a bonding temperature to form a liquid that solidifies, creating a strong and thermally stable bond with customized properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If welding or brazing is used to join metal components, then the bond strength is improved, but the polymer or composite substrate deforms or destroys due to high temperatures

Engineering Contradiction:

Improvebond strengthVSAvoidthermal damage to polymer substrate

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

An interlayer comprising a eutectic alloy is positioned between the metal component and the metal-plated non-metallic component. The eutectic alloy has a melting point lower than both the metal component and the metal-plated non-metallic component, allowing it to melt and form a liquid phase at bonding temperatures that would otherwise damage the polymer substrate. This liquid phase enables bonding while protecting the substrate from direct exposure to harmful temperatures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The eutectic alloy interlayer undergoes a phase transition from solid to liquid at the bonding temperature, which is below the melting points of the substrate materials. This transient liquid phase allows for effective bonding, and then the liquid phase solidifies to form a strong joint. The phase transition enables bonding at temperatures that protect the polymer substrate from thermal damage.

Inventive Principle:

Principle #36Phase transitions

2Ease of manufacture

If conventional coating methods like cold spraying are used, then a metallic interlock is provided, but the bond is not robust or thermally stable

Engineering Contradiction:

Improvecoating application simplicityVSAvoidbond thermal stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The bonding temperature is controlled to be above the melting point of the eutectic alloy interlayer but below the melting points of the metal component and metal-plated non-metallic component. This precise temperature parameter control enables the interlayer to melt and form a strong bond while preventing damage to the substrate materials, achieving both ease of manufacture and bond reliability.

Inventive Principle:

Principle #35Parameter changes

3Strength

If standard bonding temperatures are used for metal components, then the metal bond is strong, but the metal-plated non-metallic component cannot be joined

Engineering Contradiction:

Improvemetal bond strengthVSAvoidcompatibility with non-metallic materials

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The interlayer is formed from a eutectic alloy, which is a composite material consisting of two or more metals that melt at a lower temperature than their individual components. This composite interlayer enables bonding of dissimilar materials (metal and metal-plated non-metallic components) at temperatures that protect the non-metallic substrate while still providing strong bond strength.

Inventive Principle:

Principle #40Composite materials

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 method enables the joining of metal-coated non-metallic components without deformation, providing a robust and thermally stable bond with enhanced properties, such as increased melting point, and allows for customized coatings with a blend of substrate and coating properties.

Implementation Method 1

heating the bond region to a bonding temperature to produce a liquid at the bond region

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

maintaining the bond region at the bonding temperature until the liquid produced at the bond region has solidified to form a bond

Methodology Applied

Scientific EffectSolidification: Freezing

Data Source

PatentUS11897051B2Transient liquid phase bonding of surface coatings and metal-covered materials

Publication Date: 2024.02.13 RTX CORP

AI summary

A method for bonding components is disclosed. The method may comprise positioning an interlayer between a metallic component and a metal-plated non-metallic component at a bond region, heating the bond region to a bonding temperature to produce a liquid at the bond region, and maintaining the bond region at the bonding temperature until the liquid has solidified to form a bond between the metallic component and the metal-plated non-metallic component at the bond region. A method for providing a part having a customized coating is also disclosed. The method may comprise applying a metallic coating on a surface of a metallic substrate, and bonding the metallic coating to the metallic substrate by a transient liquid phase bonding process to provide the part having the customized coating.