An overview of the electrospark deposition process for aluminization of MCFC bipolar plates

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Abstract

The strong corrosivity of molten alkali carbonate mixtures used as electrolytes in Molten Carbonate Fuel Cells (MCFC) requires the use of corrosion-resistant stainless steels and protective surface treatments for the construction of MCFC bipolar plates and cell hardware. More specifically, the current technology involves the use of an anti-corrosive aluminization treatment to protect the so-called wet-seal areas of the stainless steel bipolar plate, namely those areas which are designed to get in direct contact with the electrolyte in order to realize an hermetic sealing condition against escapes of reactant gases or electrolyte. So far, the Ion Vapor Deposition (IVD) has been the preferred coating process for its almost unique known ability to produce high-quality diffusion iron aluminide coatings suiting for high-temperature service in hostile environments such those typically found in MCFC stacks. However, IVD is a costly method as it requires post-deposition treatments and lenghty processing times to produce the diffused iron aluminide surface layer. ElectroSpark Deposition (ESD) is a recently developed coating technology that may offer a possible and cost-effective alternative to IVD for its high suitability to treat thin metallic substrates. Being a low temperature process it is, in fact, possible to minimize mechanical deformation or warping of the substrate not easily feasible with IVD. Secondly, thanks to the ESD peculiar features, the aluminide coating is being highly diffused into the substrate material during the deposition step itself so that there is no need of subsequent heat treatments. Previous studies have demonstrated the feasibility of an ESD manual process to deposit aluminide layers onto steel foils of 0.3-0.5 mm thickness with sufficient resistance to carbonate corrosion [1,2]. However, for a fully compliance to the quality MCFC requirements the use of automatic controlled process should be developed. Here we present an overview of the characteristics of ESD process and the main expected benefits in comparison to IVD. A general evaluation of process parameters obtained with a manual ESD system is also determinated to define controllability and effectiveness of the process for subsequent experimentation on automatic systems and as basis for a preliminary cost analysis of the ESD automatic process.
Original languageEnglish
Publication statusPublished - 2005
Event1st European Fuel Cell Technology and Applications Conference 2005, EFC2005 - , Italy
Duration: 1 Jan 2005 → …

Conference

Conference1st European Fuel Cell Technology and Applications Conference 2005, EFC2005
CountryItaly
Period1/1/05 → …

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All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Frangini, S., & Masci, A. (2005). An overview of the electrospark deposition process for aluminization of MCFC bipolar plates. Paper presented at 1st European Fuel Cell Technology and Applications Conference 2005, EFC2005, Italy.