For the first time a combination of B.E.T. gas adsorption method and neutron or photon activation analysis has been successfully applied to metal surfaces as well as to metal and ceramic powders (more than 50 cases). Increasing oxide film thickness was observed with increasing Al particle size. Speciation may be performed by the analysis of dehydratation. Even double-layers in the nanometer ranges may be specified. The method satisfactorily compares with TEM.