Effect of Thermal Treatment on Chemical Interaction Between Yttrium Borosilicate Glass Sealants and YSZ for Planar Solid Oxide Fuel Cells

This article is to address the bonding and sealing capability of two yttrium borosilicate glasses. These glass seals have been tested with AISI 441 steel and high-temperature solid electrolyte that is yttria-stabilized zirconia (YSZ), as a function of different heating durations for planar solid oxide fuel cell applications in air atmosphere. The diffusion couples were prepared by slurry coating and then subjected to heat-treatment for different time durations of 1, 100, and 500 h at 850°C. In addition to this, the diffusion couples with YSZ were also thermally cycled between room temperature and 850°C. These prepared diffusion couples have been characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive spectroscopy (EDS). XRD indicated surface crystallization of the coating glass/YSZ diffusion couple. MgY glass sample shows less devitrification than the CaY glass. The overall analysis of the resulting microstructure by SEM/EDS revealed improvement in adhesion with increase in time duration of heat treatment as well as thermally cycled sample without any detrimental phase formation. The diffusion couples with AISI 441 steel have shown good adhesion with crack-free interface.