Magnetic Induction Probe for Non-Magnetic Coating Thickness

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Solution Overview

Problem

Non-destructive testing methods fail to accurately measure the thickness of non-magnetic thermal barrier coatings (TBC) applied over conductive metallic bond coats (MBC) on complex geometries of gas turbine components, as existing methods like eddy current and magnetic induction are not suitable for conductive coatings on non-magnetic substrates, and traditional coupon-based measurements are inadequate for representing actual coating thickness across the component's geometry.

Innovation Solution

Applying a magnetic coating on non-magnetic gas turbine components, followed by a non-magnetic coating, and using a calibrated magnetic induction probe to measure the thickness of the non-magnetic coating, allowing for accurate validation of the coating thickness without damaging the component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If eddy current or magnetic induction methods are used to measure coating thickness, then non-contact measurement is achieved, but these methods are not suitable for conductive coatings on non-magnetic substrates

Engineering Contradiction:

Improvenon-contact measurement capabilityVSAvoidapplicability to conductive coatings on non-magnetic substrates

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent introduces a magnetic coating layer as an intermediary between the non-magnetic substrate and the conductive bond coat. This magnetic layer enables magnetic induction measurement by providing the necessary magnetic properties, while the non-magnetic bond coat remains intact for its thermal barrier function. The magnetic coating acts as a mediator that allows the measurement method to work without compromising the coating system's integrity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If coupon-based measurement methods are used, then destructive testing is avoided, but the measurements do not accurately represent actual coating thickness across complex component geometries

Engineering Contradiction:

Improvenon-destructive testingVSAvoidaccuracy of coating thickness representation

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical/coupon-based measurement system with an electromagnetic field-based measurement system. Instead of using physical coupons that must be attached to representative locations, the magnetic induction probe uses electromagnetic fields to measure coating thickness directly on the component surface, providing continuous spatial coverage and eliminating the need for discrete sampling points.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic induction measurement system provides universal applicability across the entire component surface, regardless of geometry complexity. The probe can measure coating thickness at any location on the component, making the measurement method universally applicable rather than limited to specific coupon locations, thereby accurately representing the actual coating thickness distribution.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If magnetic coating is applied to enable measurement, then measurement capability is achieved, but an additional coating step is required

Engineering Contradiction:

Improveability to measure non-magnetic coating thicknessVSAvoidnumber of coating steps

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the magnetic properties parameter of the coating system by introducing a magnetic coating layer. This parameter change enables the measurement capability while maintaining the functional integrity of the original coating system. The magnetic coating's properties are specifically selected to provide sufficient magnetic signal for induction measurement while not interfering with the thermal barrier function of the bond coat.

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

Enables precise measurement of non-magnetic coating thickness on complex geometries, reducing the need for destructive testing and improving the accuracy of coating uniformity across the component's surface, thereby enhancing the thermal barrier and aerodynamic performance of gas turbine components.

Implementation Method 1

measuring the thickness of the non-magnetic coating with a magnetic induction probe

Methodology Applied

Scientific EffectMagnetic induction: Electromagnetic Induction

Data Source

PatentUS11143620B2Electromagnetic probe testing of bond coat

Publication Date: 2021.10.12 MITSUBISHI POWER AMERICAS INC

AI summary

A method for measuring a non-magnetic coating thickness upon a non-magnetic gas turbine component, such as a hot gas path component, can comprise applying a magnetic coating, such as a ferrous coating, upon the non-magnetic gas turbine component, applying a non-magnetic coating, such as a metallic bond coating, upon the magnetic coating, and measuring a thickness of the non-magnetic coating with a magnetic induction probe. The magnetic induction probe can be calibrated to the magnetic coating before the non-magnetic coating is applied. Measuring of the thickness of the non-magnetic coating can be used to validate spray patterns of automated spray processes. The magnetic and non-magnetic coatings can be stripped from the gas turbine component and used to validate additional spray patterns.