The Effects of a Filler with a High Coefficient of Thermal Expansion on a Sealant for High-Temperature (750 ~ 850℃) SOFCs

Abstract

In this study, we report that effects of a filler with a high coefficient of thermal expansion on a sealant for high-temperature (750 ~850 o C) SOFC. We designed a SiO 2 -BaO-ZnO-B 2 O 3 -Al 2 O 3 glass system with a softening temperature higher than 750 o C. The properties of the glass system show not only low volumetric shrinking but also low swelling. The glass system did not create a crystal phase during along-term heat treatment. We fabricated a seal gasket with 0, 10, 15, and 20 wt% cristobalite added as filler materials with glass powder. The coefficient of thermal expansion of the seal gasket increased according to cristobalite content. During alongterm heat treatment, the leak rate decreased by about 5% after a heat treatment in an oxidizing atmosphere at 750 o C for 2000 h, also decreasing by about 6% after a heat treatment in a reducing atmosphere at 750 o C for 1000 h.

Support effect of Mn/Na2WO4‐based catalysts in oxidative coupling of methane

“…The XRD patterns of fresh calcined CA catalyst show peaks at 2θ = 19.2°, 30.8°, 34.4°, 36.5°, 39.1°, 45.4°, 61.5° and 67.1° characteristic of cubic γ‐Al 2 O 3 with small differences resulted from its interaction with Na 2 WO 4 and Mn 2 O 3 34 . The XRD pattern of the CAS catalyst shows peaks related to α‐cristobalite at 2θ = 28.6°, 36.1° and 44.9°, and the XRD pattern of the CAT catalyst shows peaks related to anatase at 2θ = 25.3°, 39.2° and rutile at 2θ = 27.4°, 36.1°, 41.4°, 44.1°, 54.2° and 56.9° 37,38 . Although the anatase phase was used in the synthesis of the CAT catalyst, this XRD pattern shows that the anatase phase was converted to the rutile phase during the calcination of the catalyst at high temperatures.…”

“…34 The XRD pattern of the CAS catalyst shows peaks related to ⊍-cristobalite at 2⊔ = 28.6°, 36.1°and 44.9°, and the XRD pattern of the CAT catalyst shows peaks related to anatase at 2⊔ = 25.3°, 39.2°and rutile at 2⊔ = 27.4°, 36.1°, 41.4°, 44.1°, 54.2°and 56.9°. 37,38 Although the anatase phase was used in the synthesis of the CAT catalyst, this XRD pattern shows that the anatase phase was converted to the rutile phase during the calcination of the catalyst at high temperatures. Also, the peaks of MnTiO The XRD magnified patterns of treated catalysts at 800-850 °C, CH 4 /O 2 = 4 M ratios, with a GHSV of 12 000 h −1 at atmospheric pressure after 1 h activity test are shown in Fig.…”