Abstract: A solid body having extremely narrow passages formed therein for the separation and conveyance of gases by surface diffusion. Because of the relatively high flow resistance resulting from the extremely small cross sections of the passages, the gas conveyance through the solid body can be performed substantially exclusively by surface diffusion. Only those gas particles which are adsorbed on the solid body or on the wall of the passages will be conveyed through the solid body. The surface diffusion can be controlled by suitable selection of the gas/solid body combination. The diffusion is influenced particularly by the temperature of the solid body. When, in the case of a two-gas mixture, the solid body is heated to a temperature above the desorption temperature of one of the gases and below the desorption temperature of the other gas, only the gas particles of the adsorbed gas are conveyed on the passage walls by surface diffusion.

Abstract: In a planetary mill, the ratio between the angular speed of a planetary wheel and the angular speed of the sun wheel is selected based upon the ratio between the inner radius of a grinding drum connected to the planetary wheel and the radius of the sun wheel. This arrangement enables the planetary mill to be used for mechanically alloying brittle and hard materials.