Investigation the shear strength and the microstructure of the dissimilar joint of S.S310S to zirconia ceramic using filler without active elements

In this study, zirconia is joined to S.S310S using a brazing in a furnace under the argon atmosphere. The filler used in this process is a silver-based-alloy which has no active elements in its chemical composition. According to the fact that, unlike S.S310S, oxide ceramics have low wettability compared to alloy fillers, to activate the surface of zirconia with pure Ti-coating. The optimum thickness coating layer was determined to be 200nm. The purpose of surface coating is to reduce the penetration of the Ti-element on the surface of the ceramic sample and to create a TiO2 reaction layer in that area. The samples were joined by a brazing process for one hr. The results obtained from the shear test of brazed specimens showed high strength of specimens with a temperature of 1000˚C at an average of 117 MPa that compared to brazed samples at 1100˚C (96MPa), they had an increase of 21MPa. Then, for microstructural analysis and metallography of the joint area the SEM and OM, were performed. The results of elemental and linear analysis obtained from that area showed the reason for the decrease in strength with increasing temperature is due to excessive penetration of filler components then the formation of non-uniform reaction layer on the zirconia surface. The reaction layers formed in the process include Cu57Zr4 and TiO2(zirconia) and FeAg and FeCrNi (S.S310S) and AgCu phase in braze zone.