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Article
Publication date: 2 August 2019

Fupeng Cheng, Jinglong Cui, Shuai Xu, Hongyu Wang, Pengchao Zhang and Juncai Sun

The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton…

Abstract

Purpose

The purpose of this paper is to improve the surface electrical conductivity and corrosion resistance of AISI 430 stainless steel (430 SS) as bipolar plates for proton exchange membrane fuel cells (PEMFCs), a protective Nb-modified layer is formed onto stainless steel via the plasma surface diffusion alloying method. The effect of diffusion alloying time on electrochemical behavior and surface conductivity is evaluated.

Design/methodology/approach

In this work, the surface electrical conductivity and corrosion resistance of modified specimen are evaluated by the potentiodynamic and potentionstatic polarization tests. Moreover, the hydrophobicity is also investigated by contact angle measurement.

Findings

The Nb-modified 430 SS treated by 1.5 h (1.5Nb) presented a lower passivation current density, lower interfacial contact resistance and a higher hydrophobicity than other modified specimens. Moreover, the 1.5 Nb specimen presents a smoother surface than other modified specimens after potentionstatic polarization tests.

Originality/value

The effect of diffusion alloying time on electrochemical behavior, surface conductivity and hydrophobicity of modified specimen is evaluated. The probable anti-corrosion mechanism of Nb-modified specimen in simulated acid PEMFC cathode environment is presented.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 4
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 15 June 2010

Kaushik Alayavalli and David L. Bourell

The purpose of this paper is to produce electrically conductive, fluid impermeable graphite bipolar plates for a direct methanol fuel cell, using indirect selective laser…

Abstract

Purpose

The purpose of this paper is to produce electrically conductive, fluid impermeable graphite bipolar plates for a direct methanol fuel cell, using indirect selective laser sintering (SLS) and suitable post processing techniques.

Design/methodology/approach

Bipolar plates are made by the indirect SLS of graphite powder and phenolic resin mixture. The phenolic resin binder is then burnt off at a high temperature in a vacuum furnace to produce a 100 per cent carbon part. This brown part is then infiltrated using a low‐viscosity (∼5‐10  cps) cyanoacrylate to seal up the open pores, rendering the plates fluid impermeable.

Findings

It has been found that the electrical conductivity increases significantly (> 220 S/cm) with a corresponding increase in pyrolyzing temperature which correlates well with literature on the carbonization of phenol formaldehyde resins. The cyanoacrylate infiltrated parts tested under fluid pressure demonstrated no leakage through the plate, indicating full closure of open porosity.

Originality/value

This work demonstrates the capability of the SLS process to produce working bipolar plates with complex flow field designs that can be tested to verify its efficacy in a working fuel cell, thereby saving time and cost in machining natural graphite.

Details

Rapid Prototyping Journal, vol. 16 no. 4
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 2 May 2017

Saeed Reza Allahkaram and Namdar Mohammadi

This paper aims to evaluate corrosion behavior of bare and PbO2-coated stainless steel 316L, as prospective candidates for bipolar plates, in simulated proton exchange…

Abstract

Purpose

This paper aims to evaluate corrosion behavior of bare and PbO2-coated stainless steel 316L, as prospective candidates for bipolar plates, in simulated proton exchange membrane fuel cell’s (PEMFC’s) environment under operating potentials.

Design/methodology/approach

A set of potentiodynamic, as well as potentiostatic, electrochemical experiments was carried out under both anodic and cathodic potentials. Gathered data were analyzed via fast Fourier transform algorithm for further investigation. X-ray diffraction analysis was also used for determining coating characteristics upon completion of electrochemical experiments.

Findings

Results revealed that bare SS316L is a better candidate for bipolar plate material under anodic potential, as it is cathodically protected. However, PbO2-coated SS316L is favorable under cathodic potential, as bare specimen will suffer localized corrosion in the form of pitting.

Research limitations/implications

It would be of interest if all the experiments are carried out in a PEMFC stack.

Practical implications

This research strives to promote the use of electrochemical noise measurement for practical corrosion monitoring of coated bipolar plates in fuel cells.

Social implications

Improving the corrosion resistance of bipolar plates will expedite commercialization of PEMFCs, which in turn will translate into a substantial reduction in carbon footprint.

Originality/value

This research strives to promote the use of electrochemical noise measurement for practical corrosion monitoring of coated bipolar plates in fuel cells.

Details

Anti-Corrosion Methods and Materials, vol. 64 no. 3
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 1 April 2004

K.M. El‐Khatib, M.O. Abou Helal, A.A. El‐Moneim and H. Tawfik

This study investigated the corrosion stability of high velocity oxy‐fuel (HVOF) spray SUS316L coatings on aluminium substrate as lightweight bipolar plate materials for…

Abstract

This study investigated the corrosion stability of high velocity oxy‐fuel (HVOF) spray SUS316L coatings on aluminium substrate as lightweight bipolar plate materials for proton exchange membrane fuel cells (PEMFC). Contact resistance, microhardness and structure of the coatings were characterised using a four‐point probe, pneumatic microhardness, XRD and scanning electron microscope techniques. Preliminary electrochemical results indicate that the SUS316L coated plates significantly lowered the corrosion current of the aluminium substrate by more than one order of magnitude. Corrosion stability in relation to the coating thickness is discussed in terms of the structure composition and transpassivity of chromium.

Details

Anti-Corrosion Methods and Materials, vol. 51 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 20 February 2019

Jixin Han, Haibang Zhang, Juncai Sun, Wenyuan Zhao and Jinlong Cui

The purpose of this study is to improve the surface electrical conductivity and corrosion resistance of AISI430 stainless steel (430 SS) as bipolar plates for direct…

Abstract

Purpose

The purpose of this study is to improve the surface electrical conductivity and corrosion resistance of AISI430 stainless steel (430 SS) as bipolar plates for direct formic acid fuel cell (DFAFC).

Design/methodology/approach

The niobium diffusion layers have been successfully synthesized on 430 SS substrate by the plasma surface diffusion alloying technique under different diffusion alloying time.

Findings

The surface morphology of Nb-modified 430 SS prepared under the diffusion alloying time of 2 h is more homogeneous, relatively sleek and compact without surface micropore and other common surface blemishes. The potentiostatic and potentiodynamic polarization measurements manifest that Nb-modified 430 SS prepared under the diffusion alloying time of 2 h enormously ameliorate the corrosion resistance of bare 430 SS compared with other Nb-modified 430 SS samples and its corrosion current density is maintained at −1.4 µA cm−2 in simulated anodic environment of DFAFC (0.05 M H2SO4 + 2 ppm HF + 10 M formic acid at 50 °C).

Originality/value

The effect of diffusion alloying time on the corrosion resistance and surface conductivity of Nb-modified 430 SS has been carefully studied. The Nb-modified 430 SS samples prepared at the diffusion alloying time of 2 h have the best surface electrical conductivity and corrosion resistance in the simulated anodic environment of DFAFC.

Details

Anti-Corrosion Methods and Materials, vol. 66 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 1 October 2006

Ssuwei Chen, Jeremy Murphy, Jason Herlehy, David L. Bourell and Kristin L. Wood

This paper aims to present a new fabrication method for fuel cell current collectors. Demonstration of its usefulness and discussion of its impact on current collector…

Abstract

Purpose

This paper aims to present a new fabrication method for fuel cell current collectors. Demonstration of its usefulness and discussion of its impact on current collector design and performance are also given.

Design/methodology/approach

The selective laser sintering (SLS) technique is used to create green parts followed by a high temperature curing process and pressureless infiltration treatment to meet basic part design requirements.

Findings

A material system and process satisfying both manufacturing constraints and product property requirements can be used for fabrication of current collectors via SLS. Relative particle size and composition of the constituents play an important role in successful manufacture of the plates. Strategies to improve electrical conductivity are also discussed.

Originality/value

A new manufacturing method has been developed for the construction of fuel cell current collectors that could generate opportunities for performance enhancement and fuel cell application by eliminating the constraints imposed by traditional fabrication processes.

Details

Rapid Prototyping Journal, vol. 12 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 9 September 2013

Piergiorgio Alotto, Massimo Guarnieri, Federico Moro and Andrea Stella

The purpose of this paper is to show the main features of the redox flow battery technology, present the current state-of-the-art of both industrial and research systems…

Abstract

Purpose

The purpose of this paper is to show the main features of the redox flow battery technology, present the current state-of-the-art of both industrial and research systems and to highlight the main research challenges.

Design/methodology/approach

The study is based on an extensive survey of recent literature as well as on the authors' own experience in the modelling of RFB systems.

Findings

RFBs present unique features which make them suitable for distributed storage and thus particularly interesting in the context of smart grids. Current research aims at resolving some outstanding issues which still limit the widespread use of RFBs.

Practical implications

A more widespread use of energy storage technologies, and RFBs in particular, will allow a much higher penetration of renewable energy sources.

Originality/value

The paper presents one of the few comprehensive studies on RFBs including both technological and modelling aspects.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 32 no. 5
Type: Research Article
ISSN: 0332-1649

Keywords

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Article
Publication date: 1 June 2005

J. Füzi

To provide information on magnetic lens design principles for neutron beam focussing and to characterize the efficiency of these devices.

Abstract

Purpose

To provide information on magnetic lens design principles for neutron beam focussing and to characterize the efficiency of these devices.

Design/methodology/approach

Magnetostatic and neutron optical computations are presented for permanent magnet and electromagnetic hexapole lenses for neutron beam focusing. The numerical results are verified by magnetic and neutron beam measurements.

Findings

Neutron lenses built from brick‐shaped permanent magnets approximating the six‐pole Halbach structure yield relatively high field constant for a relatively small useful diameter. Electromagnets are weaker, but allow field constant adjustment.

Research limitations/implications

The main limitation of both presented solutions resides in the difficulty of obtaining high magnetic flux densities. Superconducting coils in hexapole configuration can overcome this limitation.

Practical implications

The magnetic lenses can be used for beam focusing in scattering neutron instruments. The focused beam is also polarized.

Originality/value

Analytical formulae are supplied for the neutron path calculation in a six‐pole magnetic field. An electromagnet design with permanent magnet flux enforcement is provided.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Content available
Article
Publication date: 1 December 2005

Martin Goosey

Abstract

Details

Circuit World, vol. 31 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 9 October 2009

Sanjay Jayaram

Alternative energy sources and power generation techniques for long‐term space missions are gaining importance in recent years for future bases and colonies on the Moon or…

Abstract

Purpose

Alternative energy sources and power generation techniques for long‐term space missions are gaining importance in recent years for future bases and colonies on the Moon or Mars. Current technologies used for manned or unmanned missions to the Moon or Mars use either solar panels (bulky, expensive/kilogram to space, and inefficient) or nuclear energy (extremely dangerous and unpopular). Enzyme based bio fuel cells can be used as alternative energy sources, but its survival depends on maintaining appropriate temperature and pressure in space. The purpose of this paper is to detail the concept design and development of a payload tank to house bio fuel cells for operations in space environment.

Design/methodology/approach

Details about the development of the design methodology for such housing are discussed. A full‐scale payload tank is designed to house a small biological fuel cell using space grade materials. Requirements analysis, design, validation, and manufacturing process are covered.

Findings

The outcome is a dimensionally optimized housing structure for housing biological fuel cells and maintaining the temperature and pressure for survival of the fuel cell.

Originality/value

The designed payload housing satisfies all the constraints and requirements. Furthermore, its advantages include scalability and modularity by virtue of using optimized design approach. The final product provides a planned procedure for designing larger housing for other missions.

Details

Journal of Engineering, Design and Technology, vol. 7 no. 3
Type: Research Article
ISSN: 1726-0531

Keywords

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