Flexible Insulating Coating for High-Temperature Electrical Conductors

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Solution Overview

Problem

Current insulating coatings for electrical conductors fail to maintain integrity at high temperatures, particularly above 500°C, due to limited thermal stability and mechanical flexibility, which restricts the operating temperature of electrical machines in harsh environments like nuclear reactors and advanced aircraft motors.

Innovation Solution

A method involving a flexible insulating precursor material composed of organo-alkoxides and inorganic filler particles, where the precursor material includes a non-hydrolysable organic moiety thermally stable at 150°C and another moiety that reacts to form an organic polymer, providing increased flexibility and resistance to fracture, allowing the coating to withstand temperatures above 500°C without cracking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If conventional insulating coatings (polymer-based) are used, then good mechanical properties and flexibility are achieved, but thermal stability is limited to about 250°C

Engineering Contradiction:
Improveservice temperatureVSAvoidthermal stability
Core Design Contradiction:
TemperatureVSStability of the object's composition

Solution Approach 1:

The patent applies composite materials by combining inorganic insulating material (alumina, silica, or aluminium nitride) with an organic polymer matrix. This composite structure allows the coating to achieve both the thermal stability of inorganic materials (withstanding temperatures of 500°C or higher) and the mechanical flexibility of organic polymers, resolving the contradiction between temperature resistance and compositional stability.

Inventive Principle:
Principle #40Composite materials

2Temperature

If inorganic insulating materials (alumina, silica, aluminium nitride) are applied by plasma CVD ion plating, then thermal stability is improved, but the insulator thickness is limited to around 3 to 4μm due to brittleness

Engineering Contradiction:
Improvethermal stabilityVSAvoidmechanical strength
Core Design Contradiction:
TemperatureVSStrength

Solution Approach 1:

The patent uses composite materials where inorganic insulating particles are embedded in an organic polymer matrix. This composite structure provides thermal stability from the inorganic components while the organic matrix prevents brittleness, allowing the coating to achieve greater thickness (beyond the 3-4μm limitation of pure inorganic coatings) while maintaining mechanical strength and flexibility.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs flexible shells and thin films by incorporating an organic polymer matrix that provides flexibility to the coating system. This allows the inorganic insulating material to be applied in thicker layers without becoming brittle, enabling the coating to withstand bending and mechanical stress while maintaining insulation integrity at high temperatures.

Inventive Principle:
Principle #30Flexible shells and thin films

3Strength

If high proportion of organic material is used in insulator composition, then good mechanical properties are achieved, but operating temperature is limited to a maximum of 420°C

Engineering Contradiction:
Improvemechanical propertiesVSAvoidoperating temperature
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The patent applies composite materials by dispersing inorganic insulating particles (alumina, silica, or aluminium nitride) within an organic polymer matrix. The inorganic particles provide high-temperature stability allowing operation at 500°C or higher, while the organic matrix maintains good mechanical properties, thus resolving the contradiction between mechanical strength and operating temperature.

Inventive Principle:
Principle #40Composite materials

4Reliability

If insulation material thickness is increased to withstand higher voltage, then breakdown voltage is improved, but mechanical flexibility and resistance to fracture are reduced

Engineering Contradiction:
Improvebreakdown voltageVSAvoidmechanical flexibility
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses composite materials where inorganic insulating particles are distributed within a flexible organic polymer matrix. This structure allows the coating to achieve greater thickness for higher breakdown voltage while the organic matrix maintains mechanical flexibility and resistance to fracture, preventing the brittleness that would normally accompany increased thickness of pure inorganic coatings.

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 solution achieves a coating with enhanced mechanical flexibility and dielectric strength, enabling electrical conductors to be bent without damage and maintain insulation integrity at temperatures exceeding 500°C, with a breakdown voltage exceeding 1000V and a thickness of approximately 20 microns, facilitating the use in high-temperature applications.

Implementation Method 1

the precursor material comprising: a first organo-alkoxide

Methodology Applied
Scientific EffectThermal decomposition: Pyrolysis

Implementation Method 2

another moiety which reacts to form an organic polymer

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Implementation Method 3

a flexible insulating precursor material composed of organo-alkoxides and inorganic filler particles

Methodology Applied
Scientific EffectSol-gel process: Sol

Data Source

PatentEP2294583B1Electrically insulating coating and method of formation thereof
Publication Date: 2019.01.09 UNIV OF TEESSIDE
  • EP2294583B1 patent drawingFigure 1
  • EP2294583B1 patent drawingFigure 2
  • EP2294583B1 patent drawingFigure 3

AI summary

A method of fabricating a structure comprising the steps of: providing an electrical conductor; providing a layer of a flexible insulating material on the electrical conductor, the material comprising: a first organo-alkoxide 1 R x Si(O1 R') 4-x and a second organo- alkoxide 2 R x Si(O 2 R') 4-x, where 1 R is a non-hydrolysable organic moiety thermally stable to a temperature of at least 150°C, 2 R is a non-hydrolysable organic moiety containing a functional group that can react with another like functional group to form an organic polymer, 1 R' and 2 R' are alkyl radicals and x is an integer from 0 to 3; and an inorganic filler material.