INFLUENCE OF ALUMINUM ON SPECIFIC HEAT CAPACITY AND CHANGES IN THERMODYNAMIC FUNCTIONS OF ZINC

doi: 10.25712/ASTU.2072-8921.2021.03.027

Abstract

Heat capacity is the most important characteristic of substances, and from its change with temperature one can determine the type of phase transformation, Debye temperature, energy of vacancy formation, coefficient of electronic heat capacity, and other properties. In this work, the heat capacity of the alloys of the Zn-Al system was determined in the “cooling” mode, by the known heat capacity of the reference sample of granulated zinc of the CV00 grade. For this, by processing the cooling curves of samples from alloys of the Zn-Al system and the standard, equations are obtained that describe their cooling rates. Further, according to the experimentally found values of the cooling rates of the standard and samples from alloys, knowing their masses, polynomials are established for the temperature dependence of the heat capacity of the alloys and the standard, which are described by a four-term equation. Using integrals of specific heat capacity, the temperature dependence of changes in enthalpy, entropy, and Gibbs energy is calculated. The obtained dependences show that with an increase in temperature, the heat capacity, heat transfer coefficient, enthalpy and entropy of the alloys increase, while the Gibbs energy decreases. In this case, the addition of aluminum increases the heat capacity, enthalpy and entropy of zinc, while the value of the Gibbs energy decreases.