Abstract
The article reviews the existing methods for determining the surface energy of solids. Each of the methods described is practically limited to either temperature or values that are experimentally determined with low accuracy. A method is proposed for determining the surface energy of a solid on the basis of the dimensional dependence of its physical properties (magnetic permeability, luminescence intensity, thermal conductivity, etc.). The surface energy of some nitrides, borides and carbides is determined. Its magnitude is much larger than the surface energy of pure metals. The critical radius of nitrides, borides and carbides is calculated, from which the direct Hall-Petch effect is reversed.