Surface oxide on tin and indium ultrafine particles and their oxidation process

The structure of surface oxide on tin and indium metallic particles and the ir oxidation process at a temperature higher than the melting point of the particles have been elucidated on the basis of observations using a high-re solution electron microscope (HREM). In the case of tin particles, the surf ace oxide layer spontaneously produced by exposure to air was composed of m icrocrystallites with the size of 1 similar to 2 nm. In the case of indium, the (222) crystal of In2O3 covered the surface of indium particles. In the oxidation of tin at a temperature higher than its melting point, crystal s hear structure which were present as the metal-excess Sn3O2 or Sn4O3 oxides have been found. In the case of indium particles, a definite crystallograp hic correlation, i.e., In2O3 (111) // In(110), has also been observed durin g the solidification of central metal. The fundamental behaviors of low-dim ensional In and Sn particles can be observed.