The properties of materials depend on the characteristics of the bulk and on those of the surf ace. Any change in surface characteristics affects a wide variety of material properties. During the last few years the role of surface phenomena in metallurgy has been the subject of many studies. Surface energy, surface tension, the activity of surfaces, and related problems are under discussion in the western world * as well as in the eastern world. t The relation between volume and surface properties in metals and alloys has been investigated and is still under investigation. Materials are...

wcrd than surface because-unless the sclid is suspended in a vacuum-it is in ccntact with a gas, a liquid, cr ancther sclid, and it is the interface between the sclid and the cther body which is the fccus cf interest in surface phencmena). The literature dces nct ccntain any useful definiticn cf this term. The term surface cr interface can be defined cnly if cne ccnsiders the characteristics cf the bulk material, the ccnditicn cf the surface under discussicn, the envircnment, and its reacticn with the surface. The emphasis, hcwever, shculd be given to' the problem under which the surface is...