J. Phys. Colloques 48 (1987) C6-511-C6-516
ATOM-PROBE STUDY OF Al-Nb INTERFACESK. Okuno1, H. Yamashita2, K. Oida2 et O. Nishikawa2
1 Department of Electrical Engineering, Nagasaki Institute of Applied Science, 536 Abamachi, Nagasaki 851-01, Japan
2 Department of Materials Science and Engineering, The Graduate School at Nagatsuta, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 227, Japan
Compositions of an Al-Nb interface with temperature were investigated by the high mass resolution time-of-flight atom-probe. The Al-Nb interfaces formed at room temperature exhibited an atomically abrupt interface and no mixed layer was found. The Al atoms at the abrupt atomic interface desorbed as Al2+ ions of a stronger evaporation field than that of the over- layer. This indicates that the evaporation field strength at the abrupt interfaces approximates to the evaporation field of Nb (F2= 3.7 V/Å). This indicates also that the Al-Nb binding is stronger than that of Al-Al binding. An Al-Nb mixing layer was found after heating at 500 K. The composition of the mixed layer was not uniform and varied from Nb2Al3 to NbAl, Nb3Al2 and Nb3Al with the A15 structure.