Rare earth oxide CeO2 enhanced reactive air brazing of YSZ ceramics

Cerium oxide (CeO 2 ) in the range of 0–16 mol.% is used to enhance the joint of Ag-based filler for brazing yttria-stabilized zirconia (YSZ) ceramic in the air. Ag–CeO 2 filler is first adopted to braze YSZ ceramic (3 mol.% yttria). The CeO 2 is found to cluster at the interface of YSZ and Ag seam, improving the wetting behavior of Ag-based fillers. The maximum shear strength of YSZ joints can reach 35.1 MPa using Ag–1CeO 2 fillers at 1050 °C/30 min. Moreover, CeO 2 is used to enhance the Ag–CuO filler for brazing YSZ ceramic. As the increase of CeO 2 content, the contact angle of Ag–CuO on the YSZ surface decreases first and then increases. The average shear strength could reach 76.5 MPa using Ag–CuO–8CeO 2 at 1050 °C/30 min. The CeO 2 could decrease residual stress by adjusting the linear expansion coefficient of Ag-based fillers. Therefore, this study provides a new strategy for exploring air brazing fillers.