Abstract: A method of treatment a metal powder to increase its surface area is presented. The metal powder to be treated is selected from a group consisting of tantalum, niobium and mixtures thereof. The method utilizes mechanical alloying applied to an initial selected metal powder and an auxiliary substance having relatively weak corrosion resistance as compared to that of the selected metal. The mechanical alloying is continued until a solid solution of the selected metal and the substance is obtained, in which the selected metal particle has a substantially developed surface area and is at least partly wetted with the substance substantially within a surface region of the selected metal particle. The substance is then removed from the obtained solid solution, thereby leaving the selected metal particles with the substantially developed surface area free of the substance.