Corrosion Test Method Using Viscous Electrolyte
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Solution Overview
Problem
Current corrosion resistance test methods for coated metal materials are time-consuming and lack reliability in evaluating the performance of coating films on steel sheets under different baking conditions, making it difficult to rapidly optimize coating conditions and ensure quality control for rust prevention in vehicles.
Innovation Solution
A corrosion resistance test method using a water-containing material with a specific viscosity range (20 mPa·s to 40 mPa·s) and a urethane association type thickener, which accelerates the corrosion process by maintaining hydrogen between the surface treatment film and the metal base, allowing for faster evaluation of corrosion progression and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional accelerated corrosion tests (combined cycle test or salt spray test) are used to evaluate coating film performance, then reliable corrosion resistance evaluation is achieved, but the testing time becomes excessively long (several months)
Solution Approach 1:
The patent changes the parameter of water-containing material viscosity from conventional low viscosity to a specific range (20-40 mPa·s) to optimize hydrogen retention. This parameter modification enables the test to maintain corrosion evaluation reliability while significantly reducing testing time from several months to a practical duration, resolving the contradiction between reliability and time consumption
2Productivity
If the viscosity of water-containing material is increased to retain hydrogen, then corrosion acceleration is improved, but the material flow and penetration capability may be reduced
Solution Approach 1:
The patent specifies a precise viscosity range (20-40 mPa·s) that balances hydrogen retention capability with material flow properties. This optimized parameter range enables sufficient corrosion acceleration while maintaining adequate penetration into the coating film, resolving the contradiction between corrosion test speed and material property optimization complexity
3Reliability
If a thickener is added to control water-containing material viscosity, then hydrogen retention is improved, but the composition complexity increases
Solution Approach 1:
The patent specifies a controlled thickener content range (0.1-5 mass%) to achieve the desired viscosity (20-40 mPa·s). This quantitative control of thickener addition enables effective hydrogen retention while minimizing composition complexity, resolving the contradiction between reliability and composition complexity
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
This method enables a more reliable and accelerated corrosion resistance test for coated metal materials, reducing testing time while maintaining high accuracy in evaluating corrosion resistance, even for coated metal materials used in automotive parts.
Implementation Method 1
Hydrogen is generated by the electrolysis of water at the cathode site, where the swelling of the electrodeposition coat progresses as the cathode reaction progresses
Implementation Method 2
voltage is applied between a base of the coated metal material and the surface of the coating film, and the corrosion resistance of the coated metal material is evaluated based on the value of the current flowing with the application of the voltage
Data Source
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AI summary
A corrosion resistance test method for a coated metal material 1 that includes a steel sheet 2 and an electrodeposition coating film 4 provided on the steel sheet 2 includes the steps of disposing two water-containing material holders 11 each holding a water-containing material 6 to be in contact with the electrodeposition coating film 4 and two electrodes 12 to be in contact with the water-containing material 6 held in each of the two water-containing material holders 11, and electrically connecting, with an external circuit 7, between the two electrodes 12; and supplying a current between one of the two electrodes 12 and the other, as an anode and a cathode, respectively from a current supplier 8 provided on the external circuit 7 to bring corrosion of the coated metal material 1 to progress. The water-containing material 6 has a viscosity at 65°C of 10mPa·s or more to 40mPa·s or less.