Abstract
Studies on a microscopical rust speck calculation methods to evaluate the preventive ability of the soft film type rust preventive oils, are reported here. This evaluation method was applied to the case of Humidity Cabinet Test or Storage Box Test, and recognized to be useful compared with the result obtained from Contact Angle Test. Distribution of rust specks, calculated at random in a microscopical field of standardized magnification, follows Poisson's distribution, but that of the mean value in several fields follows normal distribution. Rust specks in the microscopical fields are influenced by surface finishing of test specimens, corrosive conditions of testing methods, test period, etc. So that it is necessary to control them for the sake of the standardization of this method.
