Low-Temperature Pressure Sintering of Base Metals Using Reducing Agents

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Solution Overview

Problem

Existing methods for low-temperature pressure sinter connections require noble metal surfaces on contact partners, which is costly and inefficient for base metals and non-metallic materials, necessitating additional processing steps.

Innovation Solution

A method involving a base metal with a metal oxide surface, treated with a reducing agent and a precious metal sintering paste, where the reducing agent reduces the metal oxide to form a metallic surface for a low-temperature pressure sintered connection, eliminating the need for noble metal coatings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If noble metal surfaces are used on contact partners for low-temperature pressure sinter connections, then reliable material connection is achieved, but manufacturing cost increases and process complexity increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The contact surfaces are pre-coated with a reducing agent before the sintering process. This preliminary action enables the base metal surfaces to be reduced in-situ during sintering, eliminating the need for pre-applied noble metal coatings while ensuring reliable connection formation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The chemical state of the contact surfaces is changed by introducing a reducing agent that transforms the metal oxide layer into metallic base metal during the sintering process. This parameter change (from oxidized to reduced state) enables direct sintering of base metals without noble metal coatings.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If noble metal coatings are applied to base metals for low-temperature pressure sintering, then material connection is enabled, but manufacturing cost increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidprecious metal consumption
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The reducing agent serves as a temporary, consumable substance that is applied to the contact surface and then consumed during the sintering process to reduce the metal oxide. This disposable approach eliminates the need for permanent noble metal coatings, reducing precious metal consumption while enabling reliable connections.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The chemical composition of the contact surface is dynamically changed during sintering by the reducing agent, transforming the oxide layer into metallic base metal. This in-situ transformation eliminates the need for pre-applied precious metal layers.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If metal oxide surfaces are directly used for low-temperature pressure sintering, then process steps are reduced, but connection reliability deteriorates

Engineering Contradiction:
Improveprocess simplicityVSAvoidconnection reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The contact surfaces are pre-coated with a reducing agent before sintering. This preliminary preparation enables the metal oxide to be reduced in-situ during the sintering process, ensuring reliable metallic connections are formed directly on the base metal surfaces without requiring separate reduction or coating steps.

Inventive Principle:
Principle #10Preliminary action

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

Enables durable and cost-effective connections between base metal and non-metallic materials without the need for noble metal surfaces, simplifying the process and reducing costs.

Implementation Method 1

the metal oxide layer is reduced to metal by the reducing agent

Methodology Applied
Scientific EffectReduction: Reduction

Implementation Method 2

low-temperature pressure sintered connection

Methodology Applied
Scientific EffectSintering: Sintering

Implementation Method 3

the intermetallic compound between the noble metal flakes of the sinter paste and the surface of the base metal is thus formed under the additional pressure

Methodology Applied
Scientific EffectIntermetallic compound formation: Chemical Bonding

Implementation Method 4

the acid itself oxidizes and at the same time boils or sublimes at a suitable temperature

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 5

the acid itself oxidizes and at the same time boils or sublimes at a suitable temperature

Methodology Applied
Scientific EffectSublimation: Sublimation

Data Source

PatentEP2390914B1Assembly of two connection partners with low temperature pressure interconnection and method for producing same
Publication Date: 2013.11.20 SEMIKRON DANFOSS ELEKTRONIK GMBH & CO KG
  • EP2390914B1 patent drawingFigure 1a~1c
  • EP2390914B1 patent drawingFigure 1d~1e
  • EP2390914B1 patent drawingFigure 2

AI summary

The application relates to an arrangement with a first and a second joining partner that are metallurgically bonded to one another by means of a low-temperature pressure sintering process. The associated method comprises the following steps: providing a first joining partner with a surface section made of a base metal bearing a planar metal oxide layer; applying a reducing agent to the area of ​​the surface section designated as the first contact surface of the first joining partner; applying a layer of sintering paste to the reducing agent; arranging the second contact surface of the second joining partner on the layer of sintering paste; and subjecting the arrangement to temperature and pressure to form the metallurgically bonded low-temperature pressure sintering connection.