Contents 

Introduction

ASTM G148-97: Standard Practice for Evaluation of Hydrogen Uptake, Permeation, and Transport in Metals by an Electrochemical Technique

Devanathan-Stachurski Electrochemical Cell Set Up as Per the ASTM Guidelines

BASi Electrochemical-H-Cell Options

Floating Ground Potentiostat / Galvanostat Options with Techniques for Corrosion Analysis

PSTrace Software Platform

Published Literature Article: Hydrogen Permeation Analysis Using PalmSens

---

 

Introduction

For targeted applications in high-pressure hydrogen gas vessels and pipelines, carbon and low-alloy steels are the most commonly available structural materials. Apart from the low cost, a wide range of properties can be achieved through alloying, processing, and heat treatment. The containment and transport of high-pressure hydrogen gas in steel structures presents a particular challenge. Hydrogen gas can adsorb and dissociate on the steel surface to produce atomic hydrogen. The subsequent dissolution and diffusion of atomic hydrogen into steels can degrade mechanical properties, a phenomenon referred to as hydrogen embrittlement. Hydrogen reduces typical measures of fracture resistance such as tensile strength, ductility, and fracture toughness, accelerates fatigue crack propagation, and introduces additional material failure modes. Steel structures that do not fail under static loads in benign environments at ambient temperature may become susceptible to time-dependent crack propagation in hydrogen gas. These problems can affect the safety and reliability of engineering systems such as aircraft and aerospace structures, nuclear and fossil fuel power plants, oil and gas pipelines, field equipment, chemical plants, and marine structures, causing serious human, environmental, and financial losses.

In 2007, a routine gaseous hydrogen (GH2) delivery resulted in a fatal hydrogen explosion at a power plant in Muskingum, Ohio. WHA International was called upon to investigate the failure and understand how hydrogen safety could be improved to prevent future incidents. (https://wha-international.com/case-study-power-plant-hydrogen-explosion/)

 

ASTM G148-97: Standard Practice for Evaluation of Hydrogen Uptake, Permeation, and Transport in Metals by an Electrochemical Technique

This standardized protocol is a procedure for the evaluation of hydrogen uptake, permeation, and transport in metals using an electrochemical technique which was developed by Devanathan and Stachurski. While it is primarily intended for laboratory use, such measurements have been conducted in field or plant applications. It describes the calculation of effective diffusivity of hydrogen atoms in a metal while distinguishing for reversible and irreversible trapping. This practice gives guidance on preparation of specimens, control and monitoring of the environmental variables, test procedures, and analyses of results. In modern world corrosion studies, it can be applied in principle to all metals and alloys that have a high solubility for hydrogen, and for which the hydrogen permeation is measurable.

 

Devanathan-Stachurski Electrochemical Cell Set Up as Per the ASTM Guidelines

- The experimental set-up shall consist of a separate charging and oxidation cell of a form like figure below (The schematic diagram is an optimized version taken from the book chapter mentioned). Sealed oxidation cells, in which an additional material (usually palladium), either plated or sputter deposited onto or clamped against the specimen and the flux exiting this additional material is measured may be used if it is demonstrated that the introduction of this additional interface has no effect on the calculated diffusivity. The clamping of this additional material may provide inaccurate permeation currents in some systems due to the barrier effect at the interface (that is, oxides, air gaps and so forth will function as a diffusion barrier).

- Non-metallic materials which are inert to the test environment should be used for cell construction.

- At temperatures above 50°C, leaching from the cell material (for example, silica dissolution from glass in some environments) can modify the solution chemistry and may influence hydrogen permeation.

- Polytetrafluoroethylene (PTFE) is an example of a material suitable for elevated temperatures up to about 90°C.

- Where metallic chambers are necessary (for containment of high-pressure environments), the materials chosen shall have an extremely low passive current to ensure minimal effect on the solution composition and shall be electrically isolated from the membrane.

- The O-ring seal material should be selected to minimize degradation products from the seals and contamination of the solution. This problem is particularly of concern with extremely aggressive environments and at high test temperatures.

- Double junction reference electrodes may be used where necessary to avoid contamination of test solutions. At elevated temperatures, the use of a solution conductivity bridge arrangement with suitable inert materials is recommended.

- The location of the reference electrode in each compartment shall ensure minimal potential drop between the specimen and the reference electrode. A Lugging capillary may be useful in cases where the solution resistivity is high, small cell volumes are used and long tests are conducted.

- Recording of oxidation (and, as appropriate, charging) current shall be made using a standard resistor and a high internal impedance digital voltmeter or by direct measurement using a current monitoring device. Two floating ground potentiostats/ galvanostats can be used simultaneously to conduct the hydrogen permeation test.

- The measurement devices should be traceable to national standards and calibrated prior to testing.

- In some cases, stirring of the solution in the charging cell may be required. This should be performed using suitable stirring motor and apparatus.

 

Floating Ground

Ohtsuka, T., Nishikata, A., Sakairi, M., Fushimi, K. (2018). Hydrogen Embrittlement and Hydrogen Absorption. In: Electrochemistry for Corrosion Fundamentals. SpringerBriefs in Molecular Science. Springer, Singapore. https://doi.org/10.1007/978-981-10-6820-1_5

 

 

BASi Electrochemical-H-Cell Options

Customizable H-Cell Kits for Hydrogen Permeation(Devanathan-Stachurski), HER/OER Water Splitting, CO2 reduction and Membrane Resistivity Analysis:

The IP-HC cell configurations (25-1000mL volume) are a fully equipped, horizontally mounted and a dual compartment electrochemical H-Cell set-up for a wide variety of studies that require a separate compartment for counter and / or reference electrodes. The construction is gas-tight having two separate chambers each with 25-1000 ml volume capacity and each equipped with gas inlet and outlet option. This allows bubbling the solution and evacuating gases. Chambers can be separated with an ion-exchange membrane, so the electrochemical products appearing at working and counter electrode do not affect the opposite electrode. A pack (Qt. 5) of Nafion N117 membrane equivalent can be provided upon request. Upon request, each chamber can be temperature controlled using a glass tube that can be placed inside each chamber. Set-up is compatible with a power source meter or a typical Potentiostat / Galvanostat.

Technical Specification Sheet

Video: How to set-up BASi H-cell and Photo-EC H-Cell

Available Volumes: 25 mL, 50 mL, 100 mL, 250 mL, 500 mL, and 1000 mL

H-Cell Accessories:

- IP-GC-50H-1P: A pair (Qt. 2) of thermal control glass tube coils for temperature control in each chamber of IP-HC50 and IP-PECHC50 cells.

- IP-HC-Lug-M-50: Lugging tube for Ref. Electrode near membrane in IP-PECHC50 or IP-HC50.

- IP-N117-Eq: Hydrogen permeation membrane Equivalent to N117 - 5/pack for H-CELLS and PEC H-CELLS. Thickness: 183 µm, Diameter: 35mm, Density: 360 g/m2

Recommended Optional Items: Reference Electrodes (Aqueous or Non-Aqueous), Working Electrode, Auxiliary (Counter) Electrodes , MF-2024: Working electrode (flat samples like ITO) holder.

 

Floating Ground Potentiostat / Galvanostat Options with Techniques for Corrosion Analysis

PalmSens4 is a USB and battery-powered hand-held Potentiostat, Galvanostat, and Electrochemical Impedance Spectroscopy (EIS) analyzer. It has an ideal potential range (-10V to 10V) and current range (100 pA to 10 mA) for hydrogen permeation and wide variety of corrosion measurements with a high resolution and low noise. This instrument’s compact and rugged design makes it ideal for field studies as well. Its available in single or multichannel configurations.

PalmSens4 allows for a wide range of corrosion analysis methods apart from hydrogen permeation such as polarization curves to extract the Tafel slopes, corrosion rates, corrosion current, apply a current to the surface for electroplating, deposit films, or force corrosion to happen. Additionally, you can perform EIS (Electrochemical Impedance Spectroscopy) from 0.1 µHz to 1 MHz, which will allow you to extract the coating resistance, the polarization resistance, the pore resistance, the coating capacitance, water uptake of a coating and to estimate the time to failure (TTF). The instrument comes with PSTrace5 software which allows for different corrosion analytical techniques for automatic or manual analysis.

For our customers dedicated to corrosion research, we offer an EIS Plus Corrosion Package that includes PalmSens4-EIS Analyzer together with our Corrosion Handbook and a ASTM grade Corrosion Cell Kit. We also offer more than 15 varieties of corrosion cells (that can be customized) to facilitate the modern world needs of our customers. They can simply pick according to their requirements for paint-test, welded-joint tests for analysis in screws or curved surfaces, ASTM grade 1L testing, flat cells, large surface area coupons, cylindrical coupons, multi-port testing and more.

 

PSTrace Software Platform

The PalmSens4 Potentiostat also includes our complementary PSTrace Software Platform that is equipped with a sophisticated mode for Corrosion Analysis that provides more than 20 modern world corrosion analysis techniques ready-to-go for Tafel-slope based Corrosion Rate Studies, Open Circuit Voltage, Linear / Galvanostatic Polarization, Galvanostatic Cycling, Corrosion potential analysis, hydrogen permeation analysis in floating mode, and much more.

 

Published Literature Article: Hydrogen Permeation Analysis Using PalmSens

“Our humble thanks to the authors for acknowledgement of PalmSens potentiostats in this work and showing our other users how to conduct hydrogen permeation measurements using PalmSens in an efficient way.” – BASi Electrochemistry Team

“Inhibition effects of ionic and non-ionic derivatives of imidazole compounds on hydrogen permeation during carbon steel pickling.” Journal of materials research and technology 2022; Vol. 16; Page: 1324-1338. https://doi.org/10.1016/j.jmrt.2021.12.068

Literature Summary:
In this work, the authors show that the best corrosion inhibition does not always indicate the best hydrogen permeation inhibition. The imidazole-based compounds were studied as hydrogen permeation inhibitors during carbon steel pickling in hydrochloric acid at high concentration. The determination of hydrogen permeation transients was performed using a Devanathan-Stachurski type cell (Figure below). On the cathodic side of the cell, atomic hydrogen was generated during pickling of the steel in aqueous HCl solution, in the absence and presence of the inhibitors, at 25 °C. A solution of 0.2 mol L^-1 NaOH was used on the detection side. The counter and reference electrodes were a Pt wire and Ag/AgCl/KCl sat, respectively. Before voltammetric curve acquisition, the steels were kept immersed in NaOH solution for 1 h at 25 °C. Hydrogen permeation transients and voltammetric curves were obtained using EmStat3+  potentiostats from PalmSens. The gravimetric method was used to determine the corrosion resistance, by weighing the steel before and after pickling in aqueous HCl solution in the Devanathan-Stachurski cell. The difference between the initial and final weights provided an estimation of the corrosion efficiency. For more details, the readers are advised to get full text for this open access article.



The figure below shows the hydrogen permeation transients for the SAE 1020 steel with thickness of 1.3 mm, during pickling in aqueous 5.4 mol L^-1 HCl solution. The potential selected for the permeation measurements was 0.0 V (vs. Ag|AgCl|KClsat). At this potential, the steel had been passivated. Hence, the current density could be linked to the atomic hydrogen formed at the other side of the sample (the hydrogen generation side). The variation of the current density was associated with addition of the HCl solution at the side of the cell responsible for hydrogen generation. Before the HCl addition, in the first region (region 1), the current densities were associated with the transport of iron ions through the oxide film. At 2.5 h, the HCl solution was added at the hydrogen generation side. After 15 min, the current density increased until reaching the steady-state permeation current, ip ss (region 2). The duration of this transient process was approximately 1 h and 11 min. In region 3, the current density was approximately 8 mA cm^-2. In order to ensure that the current density was associated with hydrogen permeation, the HCl solution was removed from the hydrogen generation side. After this, the current density decreased exponentially as a function of time (see the insert in Figure below), showing the effect of removal of the HCl solution on the hydrogen generation. Authors have examined in details the effect of inhibitors on the hydrogen permeation along with the necessary evaluation of diffusion coefficients and more. We advise our readers to refer to this open access article for more information.



 

 

Resources: 

Electrochemical Corrosion Solutions Brochure

Corrosion Knowledge Base: Articles, Technical Notes and Concepts

EC Applications Applications Support 

Posted November 19, 2024