Effect of additive particle size on the CuO-accelerated formation of LaFeO3 perovskite conversion coatings in molten carbonate baths

Frangini, S.; Seta, L. Della; Paoletti, Claudia

doi:10.1016/j.surfcoat.2019.06.029

Cited by 7 publications

(13 citation statements)

References 23 publications

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“…The LaFeO 3 perovskite coating is obtained by simple immersion in the process bath at around 600 °C with reaction times typically in the order of hours. Besides the additions of La 2 O 3 and MgO, minor amounts of chemical accelerants can be added to the eutectic binary Li 2 CO 3 ‐Na 2 CO 3 salt as optional ingredients , , , . The process is applicable to stainless steels with either ferritic or austenitic structures, although best results can be obtained with ferritic steels due to a much better thermal matching with perovskite oxides.…”

Section: Methodsmentioning

confidence: 99%

“…Figure 1 reports an idealized open circuit potential (OCP) curve to illustrate the various stages of the LaFeO 3 perovskite coating formation process. More detailed information on these aspects can be found elsewhere [22,23,25,32]. Upon immersion, rapid chemical dissolution of the native oxide layer present on the steel surface takes place.…”

Section: The Perovskite Coating Processmentioning

confidence: 99%

“…Additives can be used to accelerate the coating-forming reactions with the aim to reduce the immersion times to a few hours compared to the tens of hours of non-accelerated processes [23,32]. In this respect, the perovskite conversion coating shares many commonalities with conventional iron phosphatizing baths since it may be similarly accelerated by oxidizing agents and semi-noble metals.…”

Section: The Perovskite Coating Processmentioning

confidence: 99%

“…In this respect, the perovskite conversion coating shares many commonalities with conventional iron phosphatizing baths since it may be similarly accelerated by oxidizing agents and semi-noble metals. Our recent studies focus on processes accelerated by galvanic coupling with copper oxide, which has demonstrated to be a powerful accelerant by supplying a high number of low-overpotential cathodic sites on the oxidized steel surface [25,26,32]. Perovskite formation takes place with presence of metallic copper deposited on the surface and also inside the coating.…”

Section: The Perovskite Coating Processmentioning

confidence: 99%

“…The two characteristic OCP regions corresponding to the spinel precursor and perovskite growth stage are also highlighted. A thin gold wire dipped in the same molten carbonate bath served as stable pseudo-reference electrode [32].…”

Section: The Perovskite Coating Processmentioning

confidence: 99%

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Perovskite Conversion Coatings as Novel and Simple Approach for Improving Functional Performance of Ferritic Stainless Steel SOFC Interconnects

et al. 2020

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A novel type of iron conversion process has been recently developed to produce dense and adherent LaFeO3 perovskite coatings onto ferritic stainless steel surfaces by reaction with La2O3 dissolved in specially‐formulated alkali molten carbonate baths. The major application of LaFeO3 perovskite coatings is for use as electrically conductive and Cr barrier layers for enhancing the functional performance of solid oxide fuel cell (SOFC) stainless steel interconnects. An overview of the molten salt bath conversion process including the effect of chemical accelerants on structure and morphology of the deposited perovskite coatings is illustrated in this work. Latest results on SOFC coating functional properties obtained in recent European Union (EU) funded projects are also briefly mentioned. In particular, the tight correlation between coating thickness and electrical functional properties in terms of area specific resistance is highlighted here. Although thickness dependency may indicate a mediocre electrical conductivity of LaFeO3 coatings produced by the conversion process, nonetheless very promising ASR results could be obtained in SOFC cathode environments at 700 °C with optimized coating structures and appropriate low coating thickness, thus suggesting a high potential of the conversion process for SOFC interconnect applications.

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Section: Methodsmentioning

confidence: 99%