Coated Metal Corrosion Testing With Insulated Temperature Control

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Solution Overview

Problem

Existing corrosion resistance test methods for coated metal materials are unreliable due to leakage currents caused by direct contact between the metal base and temperature control elements, which compromises the accuracy and reliability of the test results.

Innovation Solution

A corrosion resistance test apparatus and method that uses an insulating portion between the temperature control element and the coated metal material to prevent leakage currents, while controlling temperature and measuring the expansion of the surface treatment film to accurately assess corrosion progress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a temperature control element made from metal is used to control the temperature of the coated metal material, then the thermal conductivity is ensured and temperature control efficiency is improved, but leakage current flows through the contact portion when the metal base is exposed, lowering test reliability

Engineering Contradiction:
Improvetemperature control efficiencyVSAvoidtest reliability
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

An insulating portion is introduced as an intermediary between the temperature control element and the coated metal material. This insulating portion prevents direct electrical contact between the metal base and the temperature control element, thereby blocking leakage current paths while still allowing thermal energy transfer to maintain effective temperature control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the metal base is directly contacted by the temperature control element, then simple thermal contact is achieved, but leakage current compromises the accuracy of corrosion resistance measurement

Engineering Contradiction:
Improveassembly simplicityVSAvoidcorrosion resistance measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The insulating portion serves as a mediator that maintains thermal contact while preventing electrical contact. This allows the temperature control element to remain in contact with the coated metal material for efficient heat transfer, but the insulating property blocks the leakage current that would otherwise interfere with corrosion resistance measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If damaged portions reaching the metal base occur during handling, then the coating integrity is compromised, but direct contact between exposed metal and temperature control element creates leakage current

Engineering Contradiction:
Improvehandling flexibilityVSAvoidtest reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The insulating portion is pre-installed on the temperature control element before testing begins. This beforehand protective measure ensures that even if the coating is damaged during handling and the metal base is exposed, the insulating portion will prevent leakage current from flowing, thus protecting test reliability from potential handling damages.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 apparatus and method provide a highly reliable and efficient evaluation of corrosion resistance by preventing leakage currents and accurately measuring the expansion of the surface treatment film, allowing for rapid and quantitative assessment of corrosion progression.

Implementation Method 1

a temperature control element which has an insulating portion disposed on a surface of the temperature control element, is brought into contact with the coated metal material via the insulating portion, and is configured to control a temperature of at least the coated metal material

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

supplying a current between the electrode and the metal base, or between one of the two electrodes and the other, as an anode and a cathode, respectively to bring corrosion of the coated metal material to progress

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Implementation Method 3

one or two water-containing material holders disposed on the surface treatment film to hold a water-containing material that is in contact with the surface treatment film inside

Methodology Applied
Scientific EffectIon transport: Ion Exchange

Data Source

PatentEP3945303B1Corrosion resistance test apparatus and corrosion resistance test method for coated metal material
Publication Date: 2025.08.27 MAZDA MOTOR CORP
  • EP3945303B1 patent drawingFigure 1
  • EP3945303B1 patent drawingFigure 2
  • EP3945303B1 patent drawingFigure 3

AI summary

A corrosion resistance test apparatus 100 is for a coated metal material 1including a steel sheet 2 and an electrodeposition coating film 4 provided on the steel sheet 2. The corrosion resistance test apparatus 100 includes: two water-containing material holders 11 disposed on the electrodeposition coating film 4 to hold a water-containing material 6 that is in contact with the electrodeposition coating film 4 inside; two electrodes 12 in contact with the water-containing material 6 contained in each of the two water-containing material holders 11; an external circuit 7 configured to electrically connect between the two electrodes 12; a temperature control element 41, 43 that is brought into contact with the coated metal material 1 via an insulating portion 42, 44 and is configured to control a temperature of at least the coated metal material 1; a control device 9 connected to the temperature control element 41, 43 and configured to control a temperature of the temperature control element 41, 43; and a current supplier 8 provided on the external circuit 7 and configured to supply a current between one of the two electrodes 12 and the other, as an anode and a cathode, respectively to bring corrosion of the coated metal material 1 to progress.