Ceramics Paste Additives for NOx Sensor Cut Surface

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Solution Overview

Problem

The existing methods for producing NOx sensors with laminated bodies often result in rough cut surfaces during cutting, leading to cracking issues after firing, which affects the reliability and performance of the sensors.

Innovation Solution

A ceramics paste is developed containing ceramic particles, a butyral resin, a solvent, and specific additives, such as those with alkenylimidazoline structures and polyoxyalkylene condensates, which improve the adhesion properties of the cut surface, reducing surface roughness and cracking rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional ceramics paste is used for producing laminated bodies, then the manufacturing process is simple, but the cut surface becomes rough leading to cracking after firing

Engineering Contradiction:
Improvecut surface smoothnessVSAvoidcracking resistance
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention changes the chemical composition parameters of the ceramics paste by adding specific additives (alkenylimidazoline structure compounds and polyoxyalkylene condensates) to modify the adhesion properties of the cut surface, thereby reducing surface roughness and preventing cracking after firing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The additives act as intermediary substances between the ceramic particles and the binder resin, improving the adhesion state at the cut surface and preventing the roughness that leads to cracking during subsequent firing processes

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the adhesion state of cut surface is not adjusted, then the manufacturing process is straightforward, but the cracking rate increases reducing manufacturing yield

Engineering Contradiction:
Improvemanufacturing yieldVSAvoidcracking rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

By modifying the compositional parameters of the ceramics paste to include specific additives, the invention improves the adhesion state of the cut surface, thereby reducing cracking rates and increasing manufacturing yield without complicating the overall process

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The additives are incorporated into the ceramics paste before cutting, performing preliminary action to ensure proper adhesion at the cut surface before the cracking can occur during firing, thus preventing defects in advance

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

The use of the ceramics paste with additives results in a smoother cut surface, reducing the occurrence of cracking and enhancing the manufacturing yield of NOx sensors by adjusting the adhesion state of the cut surface, thereby improving the reliability and performance of the laminated body.

Implementation Method 1

The use of the ceramics paste with additives results in a smoother cut surface, reducing the occurrence of cracking and enhancing the manufacturing yield of NOx sensors by adjusting the adhesion state of the cut surface

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2664599B1Ceramics paste and laminated body
Publication Date: 2019.11.20 NGK INSULATORS LTD
  • EP2664599B1 patent drawingFigure 1
  • EP2664599B1 patent drawingFigure 2
  • EP2664599B1 patent drawingFigure 3

AI summary

A NOx sensor 100 is produced by forming a stack with a ceramics paste including ceramic particles, a resin, a solvent, and one or more additives selected from additives of a first group having a first structure containing one or more selected from ether structures, urethane structures, hydroxy group-containing structures, ester structures, and acrylic structures and additives of a second group having any one or more structures of the additives of the first group and a second structure containing one or more selected from imidazoline structures, ethylenediamine structures, and amine structures. The ceramics paste contains any one of the additives of the first group and the second group and thus has an appropriate affinity for a cutting edge at the time of cutting a laminated body before the firing of the NOx sensor 100.