Cermet Electrical Feedthrough Sintering at Ultra-Low Air Partial Pressure

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Solution Overview

Problem

Existing sintering processes for ceramic materials, particularly for cermet-containing electrical feedthroughs, are inefficient and result in suboptimal hermetic tightness due to uncontrolled gas compositions and high porosity, leading to cracks and reduced mechanical and thermal stability.

Innovation Solution

Sintering ceramic materials at elevated temperatures in a controlled gas atmosphere with reduced partial pressure of atmospheric air, typically less than 10^-6 times that of ambient air, to create a hermetically tight and crack-free cermet-containing electrical feedthroughs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sintering is carried out in uncontrolled room air atmosphere, then the process is simple and inexpensive, but hermetic tightness is insufficient and cracks form

Engineering Contradiction:
Improvehermetic tightnessVSAvoidgas atmosphere control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies inert atmosphere principle by replacing uncontrolled room air with controlled gas atmospheres having reduced oxygen partial pressure (below 10^-6 atm). This prevents harmful oxidation reactions during sintering of cermet components, ensuring hermetic tightness and crack-free bonding between ceramic base body and metallic conduit elements.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent implements parameter changes by precisely controlling gas atmosphere composition (oxygen partial pressure below 10^-6 atm) and sintering temperature profiles. These parameter optimizations enable complete densification and hermetic sealing without crack formation, resolving the contradiction between reliability and process complexity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If sintering is performed at high pressure to support the process, then sintering support is improved, but equipment complexity and cost increase

Engineering Contradiction:
Improvesintering qualityVSAvoidpressure control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces high-pressure requirements with controlled low-oxygen atmosphere conditions. By maintaining oxygen partial pressure below 10^-6 atm through inert gas environments, the process achieves hermetic sintering quality without requiring complex high-pressure equipment, thus resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Strength

If conventional sintering processes are used, then the process is straightforward, but porosity remains high and mechanical stability is reduced

Engineering Contradiction:
Improvemechanical stabilityVSAvoidporosity control
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent achieves precise porosity control and enhanced mechanical stability by optimizing sintering parameters including oxygen partial pressure (below 10^-6 atm), temperature gradients, and holding times. These controlled parameter changes enable complete densification while maintaining manufacturing process feasibility.

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 produces sintered workpieces with enhanced hermeticity, reduced porosity, and improved mechanical and thermal stability, ensuring high tightness and minimal crack formation.

Implementation Method 1

sintering of a ceramic material at a temperature of at least 1000°C and in an atmosphere, in the case of which the partial pressure of atmospheric air is reduced to less than 10^-6 times that of ambient air

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3929170B1Sintering process for electrical feedthroughs
Publication Date: 2025.08.06 HERAEUS MEDEVIO GMBH & CO KG
  • EP3929170B1 patent drawingFigure 1~2
  • EP3929170B1 patent drawingFigure 3~4
  • EP3929170B1 patent drawingFigure 5A~5D

AI summary

The invention relates to a process for producing a sintered workpiece, which comprises sintering of a ceramic material at a temperature of at least 1000°C and in an atmosphere, in the case of which the partial pressure of atmospheric air is reduced to less than 10-6-times, based on the ambient air at the same temperature under equilibrium conditions.