One of the most effective methods of increasing the wear resistance, hardness, surface strength and high-temperature oxidation resistance of metals and alloys is the diffusion satu­ ration of the surfaces by metals and nonmetals. For communicating and discussing the results of the numerous researches carried out in this field in the Department of PJ:tysicotechnical Problems of Materials Science, Academy of Sciences of the UkrSSR, a permanent Scientific Seminar was set up in 1961, which enjoys an ever-increasing popularity among specialists in this field. The present collection contains papers read at the Third Session of this Seminar, held on September 25-28, 1963. The compilers of the collection and the authors of the papers hope that its publication in the U. S. A. will enable American specialists to become acquainted with the main lines along which corresponding work is being conducted in the USSR. This should contribute to an ex­ change of scientific experience in this interesting field which is of such great practical impor­ tance. G. V. Samsonov PREFACE This collection is comprised of papers relating to the diffusion saturation of metals and to coatings of refractory compounds. The papers discuss current problems in the theory and practice of the production of diffusion coatings on metallic materials. A means of classifying the methods of diffusion saturation is proposed, and a new method is described for calculating the diffusion parameters in a heterogeneous medium.