Indexed on: 12 May '15Published on: 12 May '15Published in: Journal of Materials Science: Materials in Electronics
The role of active element titanium for the bonding alumina substrates using Sn3.5Ag4Ti(Ce,Ga) alloy filler at 250 °C in air was studied. The influence of soldering time on the microstructure and element distribution was investigated. It was observed that the Sn3.5Ag4Ti(Ce,Ga) solder could wet the alumina well under the agitation of external force. No continuous reaction products could be detected at the alumina/solder interface by using scanning electron microscopy and X-ray diffractometer. It might be inferred that the joining could be accomplished by chemical adsorption of Ti on the alumina/solder interface, regardless of whether or not an interfacial reaction layer is formed. The theoretical analysis of the Ti element adsorption at the alumina/solder interface was tried. Results can further explain the adsorption phenomenon of Ti at the interface prior to bond formation. In the case of environmental temperature has yet to meet the chemical reaction conditions, the chemical adsorption between active elements and alumina can get good bond as well. The shear strengths of the soldered Al2O3/Al2O3 substrates with the soldering time of 15 min, 30 min, and 1 h were measured to be 15.46, 16.15, and 17.39 MPa respectively.