Micro Coil With Heat-Resistant Coating for High-Temperature Oxidizing Environments

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Solution Overview

Problem

Conductive micro coils, such as carbon and TiC micro coils, degrade or lose conductivity in high-temperature environments with oxidizing atmospheres, making them unsuitable for use as radio wave absorbers in exhaust clean-up catalysts for internal combustion engines.

Innovation Solution

A micro coil with a heat-resistant coating layer that maintains electrical conductivity and shape, even under high-temperature and oxidizing conditions, allowing it to function as a radio wave absorber by producing induced currents and generating Joule heat when irradiated with microwaves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If carbon micro coil is used in high-temperature environment (≥500°C) with oxidizing atmosphere, then electrical conductivity is achieved, but the micro coil is oxidized and gasified

Engineering Contradiction:
Improveelectrical conductivityVSAvoidoxidation resistance
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention uses a composite structure consisting of a carbon micro coil body combined with a protective coating layer. The coating layer is formed by depositing a heat-resistant material (such as metal oxide or ceramic) on the carbon micro coil surface, creating a composite structure that combines the electrical conductivity of carbon with the oxidation resistance of the coating material, allowing the micro coil to maintain both conductivity and stability in high-temperature oxidizing environments

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The protective coating layer creates an inert barrier between the carbon micro coil and the oxidizing atmosphere. This coating layer prevents direct contact between oxygen and the carbon surface, effectively isolating the carbon micro coil from the harmful oxidizing environment while maintaining its electrical conductivity properties

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

2Stability of the object's composition

If micro coil body is made heat-resistant to prevent thermal decomposition and melting, then thermal stability is improved, but electrical conductivity may be reduced

Engineering Contradiction:
Improvethermal stabilityVSAvoidelectrical conductivity
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The invention employs a composite structure where the micro coil body is made of heat-resistant material (such as ceramic or metal alloy) that provides thermal stability, while a conductive coating layer is applied on the surface to restore and maintain electrical conductivity. This composite approach allows the micro coil to simultaneously achieve both thermal resistance and electrical conductivity in high-temperature environments

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

The micro coil with a coating layer effectively converts radio wave energy into thermal energy with higher efficiency and maintains functionality in high-temperature, oxidizing environments, preventing degradation of the micro coil body and ensuring continuous operation.

Implementation Method 1

the coating layer has a helical shape that causes induced current to be produced according to a magnetic-field component of radio waves, when the micro coil receives the radio waves

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

induced current is produced in the coating layer (in the micro coil body and the coating layer when the micro coil body also has conductivity), according to the magnetic-field component of the radio waves, and the induced current thus produced flows in the coating layer (the micro coil body and the coating layer when the micro coil body also has conductivity), to generate Joule heat

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3406872B1Micro coil
Publication Date: 2020.02.19 TOYOTA JIDOSHA KK
  • EP3406872B1 patent drawingFigure 1A~1B
  • EP3406872B1 patent drawingFigure 2A~2B
  • EP3406872B1 patent drawingFigure 3

AI summary

A micro coil includes a micro coil body (10) having heat resistance sufficient to keep the micro coil body (10) from thermal decomposition and melting in a high-temperature environment, and a coating layer (11) that is provided on a surface of the micro coil body (10), and has heat resistance and electrical conductivity under the high-temperature environment and an oxidizing atmosphere. The coating layer (11) has a shape that causes induced current to be produced according to a magnetic-field component of radio waves, when the micro coil receives the radio waves.