Non-destructive Hydrogen Diffusivity Measurement Apparatus
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Solution Overview
Problem
Current methods for measuring hydrogen diffusivity in metals are destructive and cannot be applied to installed or operational metallic structures, leading to significant discrepancies in measured values due to variations in steel microstructure, specimen thickness, and surface preparation.
Innovation Solution
A non-destructive method and apparatus that utilize a hydrogen charging surface and an oxidation surface on the external surface of the metal structure to generate and measure hydrogen flux, allowing for the determination of hydrogen diffusivity using a Fickian diffusion model or simulated master graphs, independent of geometric dimensions and experimental parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the standard measurement technique (ISO 17081) is used, then hydrogen diffusivity can be measured, but the measurement process is destructive and requires extracting test specimens from the structure
Solution Approach 1:
The patent uses electrochemical cells to create a surface-level copy of the hydrogen diffusion process without requiring extraction of test specimens. The charging cell generates hydrogen at the surface, and the oxidation cell detects it, providing a non-destructive measurement that copies the essential diffusion behavior at the surface level.
Solution Approach 2:
The patent replaces the mechanical extraction and machining of test specimens with an electrochemical measurement system. Instead of physically removing material to test hydrogen diffusion, the system uses electrochemical reactions to generate and detect hydrogen in situ, substituting mechanical destruction with chemical processes.
2Measurement precision
If test specimens are extracted and machined for measurement, then hydrogen diffusivity can be determined, but significant variability occurs due to changes in microstructure, thickness, and surface preparation
Solution Approach 1:
The patent enables the structure to serve itself as the test specimen. The in situ measurement system uses the actual structure's surface to generate and detect hydrogen, eliminating the need to extract separate test specimens. This self-service approach ensures that the measurement is performed on the actual material with its original microstructure, thickness, and surface characteristics intact.
Solution Approach 2:
The patent extracts only the necessary measurement function (hydrogen generation and detection) through electrochemical cells applied to the surface, while leaving the bulk material and its microstructure intact. This selective extraction of the measurement capability without removing material resolves the variability issue.
3Object-affected harmful factors
If non-destructive measurement methods are used, then the structure remains intact, but measurement capability is limited for installed or operational structures
Solution Approach 1:
The patent creates a universal measurement system that can be applied to any metallic structure regardless of its location or operational state. The electrochemical cells can be attached to surfaces of installed pipelines, pressure vessels, or operational equipment, providing a multi-functional solution that works across different applications and conditions without requiring structure removal or shutdown.
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 accurate, on-site measurement of hydrogen diffusivity in metals without damaging the structure, reducing variability and providing reliable data for hydrogen damage evolution models and lifetime predictions.
Implementation Method 1
Hydrogen flux is generated and directed into the metal surface at the charging surface
Implementation Method 2
Some of the hydrogen generated on the charging cell side diffuses through the sample to the oxidation cell
Implementation Method 3
hydrogen atoms are oxidized. The oxidation process is facilitated by keeping the sample at a positive potential
Data Source
Figure 1A
Figure 1B
Figure 2A~2C
AI summary
A method of measuring a hydrogen diffusivity of a metal structure is provided. The method includes providing a hydrogen charging surface at a first location on an external surface of the structure, and a hydrogen oxidation surface at a second location adjacent to the first location on the external surface of the structure. A hydrogen flux is generated and directed into the metal surface at the charging surface. At least a portion of the hydrogen flux generated by the charging surface and diverted back toward the surface is detected, and a transient of the diverted hydrogen flux is measured. The hydrogen diffusivity of the metal structure is then determined based on the measured transient.