Properties of alumina-particles-reinforced silver composite

To overcome the high-temperature defects of Ag used as the substrate of superconducting tape and improve the mechanical properties and melting point of Ag, the alumina whose melting point is high was selected as a doping to prepare Al2O3/Ag composite through conventional powder metallurgy. The results indicated that over 1wt% Al2O3 particles doped in Ag matrix can raise the melting point tm of Ag up to 970°C and 3wt% Al2O3 particles can raise that up to 990°C. It was found that among the samples doped with Al2O3 particles less than 3wt%, the 2% Al2O3/Ag composite has the maximum hardness and tensile strength and minimum linear coefficient of expansion and elongation percentage. Since the sample 2% Al2O3/Ag composite has proper melting point, suitable linear coefficient of expansion in proximity to that of the YBaCuO superconductor and best mechanical properties, it meets the posterior heat-treatment requirements for YBaCuO superconducting tapes in Ar atmosphere.