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Braze metal. Ti. YSZ. Reaction layer. Zr. 2.0 μm. Ag. Cu. 1: Monoclinic ZrO 2 2: Tetragonal ZrO 2 3: γ-AgTi 3 4: δ- TiO. Ticusil ®. (c). (b). YSZ. (a). Interface. 2.0 mm. 2θ.
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Braze metal Ti YSZ Reaction layer Zr 2.0 μm Ag Cu 1: Monoclinic ZrO2 2: Tetragonal ZrO2 3: γ-AgTi3 4: δ-TiO Ticusil® (c) (b) YSZ (a) Interface 2.0 mm 2θ Joining Yttria Stabilized Zirconia (YSZ) to Crofer22-APU® for Applications in Solid Oxide Fuel Cells Investigator: J.E. Indacochea, Department of Civil and Materials Engineering, UIC YSZ Ticusil® YSZ • Develop a filler material and brazing procedure that provides a high quality hermetic seal to enhance the performance of Solid Oxide Fuel Cells (SOFCs). • Reactive brazing has proved to be the most effective and efficient method for joining ceramics–to-metals. The addition of reactive elements to filler metals improve wetting in ceramics by the formation of a reaction layer that insures bonding. • The thickness of the reaction layer on the interface YSZ/filer metal will have an important effect on the mechanical properties of the joint. XRD spectra of interface YSZ/Ticusil®, 900°C, 60’. (a). Pure YSZ, (b). HNO3 etched interface YSZ/Ticusil®, (c). Ground interfaceYSZ/Ticusil®. • YSZ was brazed to itself and to Crofer22-APU® using Ag-Cu-Ti alloys. • Commercial alloys: Ticusil® (4.5%Ti) and Cusil-ABA® (1.5%Ti) were evaluated for joining efficiency at 900°C for 15, 30, and 60 minutes in vacuum (~6 x 10-6torr.). • Optical microscopy, electron microscopy, dispersive energy spectroscopy (SEM-EDS), and X-ray diffraction (XRD) were carried out in order to study the interface YSZ/Ag-Cu-Ti. • YSZ reacted with the active filler metals (Ag-Cu-Ti) to form a reaction layer at the interface. This reaction layer was rich in Ti and the presence of - TiO was confirmed using XRD analysis and SEM-EDS. • The thickness of the reaction layers was a function of the Ti content in the filer metal. Reaction layers for Ticusil® as a filler metal were larger than Cusil-ABA®. • The main goal is to develop a sound seal between the interconnect and the electrolyte that withstand operating temperatures up to 1000°C, using novel materials.