INSITU CORROSION STUDIES OF ALUMINUM AND ALUMINUM TANTALUM ALLOY IN 0.01M NACL USING STM

Scanning tunneling microscopy has been used to study polycrystalline aluminum and Al-Ta alloy in air and in NaCl solution. In situ study of the modification of the surface due to Al dissolution in the NaCl solution shows that the roughing process is about 10 to 40% less for the Al-Ta alloy than for the Al sample at a given time of immersion. By inductively coupled plasma analysis, it is found that the rate of dissolution of Al from the Al-Ta alloy is about 100 times slower than from the Al sample for the first 30 h of immersion. The possibility of in situ studies of the topography of oxide films by STM is discussed.