Experimental Evaluation of Planar SOFC Single Unit Cell With Crofer22APU Plate Assembly

Leone, Pierluigi; Lanzini, Andrea; Delhomme, Baptiste; Ortigoza-Villalba, G.A.; Santarelli, Massimo; Smeacetto, Federico; Salvo, Milena; Ferraris, Monica

doi:10.1115/1.4003227

Cited by 6 publications

(1 citation statement)

References 27 publications

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“…However, the interfacial phenomena are not fully understood in this system. For example, it is not clear whether Co or Ni in the alloy plays any significant role in the chemical bonding [7] or whether wustite (FeO) exists as an interlayer in the joint to bridge the metallic bond in the alloy and the ionic/covalent bond in the glass [8]. FeO is the most beneficial substances to enhance the wetting and diffusion ability between glass-to-alloy.…”

Section: Introductionmentioning

confidence: 99%

Effects of Laser Radiation on the Wetting and Diffusion Characteristics of Kovar Alloy on Borosilicate Glass

Zhang

Yao

Chen

et al. 2017

Journal of Manufacturing Science and Engineering

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The purpose of this study was to investigate the advantages of laser surface melting for improving wetting over the traditional approach. For comparison, kovar alloy was preoxidized in atmosphere at 700 °C for 10 min, and then wetted with borosilicate glass powder at 1100 °C with different holding time in atmosphere. The proposed approach used a Nd:YAG laser to melt the surface of the kovar alloy sample in atmosphere, then wetted with borosilicate glass powder at 1100 °C with the same holding time. The laser melted surface shows a decrease in contact angle (CA) from 47.5 deg to 38 deg after 100 min. X-ray photoelectron spectroscopy (XPS) analysis shows that the surface and adjacent depth have higher concentration of FeO for laser treated kovar (Kovar(L)) than that on traditional thermal treated kovar (kovar(P)). This is attributed to the following improved wetting and diffusion process. The adhesive oxide layer formed on kovar (L) may enhance the oxygen diffusion into the substrate and iron diffusion outward to form an outside layer. This is an another way to enhance the wetting and diffusion process when compared to the delaminated oxide scales formed on kovar (P) surface. The diffusion mechanisms were discussed for both approaches. Scanning electron microscope (SEM) revealed that an iron oxide interlayer in the joint existed under both conditions. Fayalite nucleated on the iron oxide layer alloy and grew into the glass. In both cases, neither Co nor Ni were involved in the chemical bonding during wetting process. The work has shown that laser surface melting can be used to alter the wetting and diffusion characteristics of kovar alloy onto borosilicate glass.

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Section: Introductionmentioning

confidence: 99%