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Author: search.filters.author.Tengprasert, WatcharaponSubject: search.filters.subject.interconnect

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    Novel Method for Determining Standard Enthalpy and Entropy of Volatilisation of Chromia Exposed to Humidified Oxygen at 298 K Based on Transport Theory of Multicomponent Gas Mixtures
    (2025-02-01)
    Thublaor, Thammaporn
    ;
    Tengprasert, Watcharapon
    ;
    Suparapinyopapkul, Grid
    ;
    Nilsonthi, Thanasak
    ;
    Chandra-ambhorn, Walairat
    Based on the transport theory of multicomponent gas mixtures, we proposed an expression for determining the standard volatilisation enthalpy and entropy of chromia exposed to humidified oxygen at 298 K. The use of this expression could lead to the quantification of those thermodynamic quantities when the mass flux of Cr loss due to the volatilisation of chromia is determined. We thus experimentally measured the mass fluxes of Cr loss due to volatilisation in humidified atmospheres at 873–1073 K. As a result, the standard enthalpy and entropy of the volatilisation of chromia subjected to humidified oxygen at 298 K were quantified, giving the values of 61.1 ± 1.0 kJ mol<sup>−1</sup> and −43.0 ± 1.9 J K<sup>−1</sup> mol<sup>−1</sup>, respectively. The measured and calculated mass fluxes of Cr loss due to volatilisation tended to be related to absolute temperature in the Arrhenius-like form. We proposed the use of the line of the mass flux of Cr loss due to volatilisation in an Arrhenius-like diagram, which was shifted by the different thermodynamic data used to graphically assess the reliability of the thermodynamic data obtained from this work and the literature.
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    Fabrication of Mn–Co Alloys Electrodeposited on AISI 430 Ferritic Stainless Steel for SOFC Interconnect Applications
    (2023-03-01)
    Thanedburapasup, Saravut
    ;
    Wetchirarat, Nattapol
    ;
    Muengjai, Angkana
    ;
    Tengprasert, Watcharapon
    ;
    Wiman, Panya
    Mn–Co alloys were electroplated on AISI 430 stainless steel using an electrodeposition technique with the aim to reduce oxidation and chromium volatilization. The electroplating parameters were designed to improve the coating quality. The increased current density with decreased MnSO<inf>4</inf> content resulted in a denser coating layer. A sample coated with 0.10 M CoSO<inf>4</inf> and 0.50 MnSO<inf>4</inf> at 350 mA cm<sup>−2</sup> showed the best oxidation resistance after being oxidized at 800 °C for 90 h. The X-ray diffraction (XRD) result revealed that the oxide growth on the surface of the coated samples mainly formed oxides of MnCo<inf>2</inf>O<inf>4</inf>, MnCr<inf>2</inf>O<inf>4</inf>, and Cr<inf>2</inf>O<inf>3</inf>. The chromium volatilization was evaluated by exposing the coated samples to humidified synthetic air at 800 °C for 96 h. The mass flux of Cr volatilization was on the order of 10<sup>−11</sup> g cm<sup>−2</sup> s<sup>−1</sup>. Furthermore, different heat treatments in O<inf>2</inf> and CO<inf>2</inf> atmospheres were compared. Annealing in CO<inf>2</inf> at 800 °C for 4 h helped increase the Mn–Co coating density. The relationship between the porosity and its failure behavior was also discussed.