Published online by Cambridge University Press: 22 February 2011
Wettability and contactibility of selected metals and alloys on superconducting YBa2Cu3O7-x were studied. Droplets of metals and alloys were formed by melting short segments of wires on pellets of YBa2Cu3O7-x The wires were melted in a rapid thermal annealer with an oxygen atmosphere to lessen the oxygen loss from the YBa2Cu3O7-x surface. The contact angles of the solidified droplets on the pellets were measured from the micrographs taken with a scanning electron microscope. Contact angles less than 90° were obtained with Pb and Ag, while angles greater than 90° were obtained with Bi metal, 40Pb/60Sn, and 99Pb/lSb alloys. Pb alloyed with either Sn or Sb increased the wetting angles. The contact angles provided a direct measurement of wetting characteristics and were used to relate various surface energies and the work of adhesion between tested metallic systems and YBa2Cu3O7-x.