Microstructures and interfacial behavior of zirconia/stainless steel joint prepared by pressureless active brazing

ZrO2 ceramic/stainless steel joints were fabricated by pressureless brazing with Ag–Cu filler metals and TiH2 powders. The microstructures and elemental distributions of the joint cross-section as well as the reaction products at the ceramic/filler interface were analyzed using SEM, EDS, XRD and XPS. The results showed that there existed three zones with a distinguished difference in microstructure crossing the brazing interlayer. A double-layer structure including a reaction layer and a sublayer was formed at the ZrO2/filler interface, where Ti4+, Ti2+ and Zr2+ were located based on the XPS spectra. It is further found that Ti originated from TiH2 coating diffused into the whole interlayer. The high activity of neonatal Ti caused the reactions of Ti/ZrO2 and Ti/Cu, resulting in the interfacial phases such as Ti3Cu3O, CuTi3 and Zr.