The metal-thermal processes, phase transition of substances, reaction of compounds i: forming are accompanied, as it is known, by thermal effects. It is accepted to connect these effects to liberation into environment (exothermic effects) or absorb of heat from environment Cendothermic effects). But such view on nature of thermal effects does not correct with the physics position. Heat does not a substance, which is able to liberate from anywhere as it gastric juice does, or to be swallowed by anything as water by sponge. The heat is a form of chaotic movement of particles (atoms and molecules), which compose the some material system. The intensity of its movement determinates the level of system thermal state. The system temperature is macroscopic parameter, which are characterizing this level.
In present work the nature of thermal effects accompanied processes of metal-thermal reduction, e. g. Fe, Ti and Cr, is considered namely from this point of view. It was shown that volumetric changes accompanied a reaction interactions lie in base of thermal effects. So named exothermic effects, which essence is expressed in the system self-heating, is stipulated by the spontaneous adiabatic compression. The effects that named as endothermic ones are connected with a system adiabatic expansion, stimulated the temperature decrease.
An elementary acts of substances transitions and reaction interactions are accomplished spontaneously and can pass in condition of system adiabatic isolation after obtaining of required level of activation energy.
The limits of volumetric changes, by which the reaction interactions, substance polymorphic transitions, spontaneous crystallization of melts, oxidation and reducing reactions, processes of new compounds synthesis etc are being accompanied, are oscillated from percent portions to tens percents in that and other side from initial values. Temperature oscillations, accompanied these effects, also has a wide diapason: from unity to tens and thousands degree as, for example, in case of aluminothermic reduction of iron and chromium.
© 2001 Gorokh Aleksey Vasilievich
E-mail: gor@konstant.ac.donetsk.ua