The temperature dependence of calorific capacity and thermodynamic function changes for the composition of lead-antimony-3 alloy and calcium

This article deals with lead-antimony alloys that are characterized by simple eutectic and low mutual solubility of their components (up to 3.5% of the Sb mass) and have high mechanical integrity and casting properties. These alloys are widely used in the battery production industry for accumulator grids manufacturing and, in some cases, for the molding of anodes for the electrolysis of sulfuric acid solutions of zinc, cadmium, and manganese. The lead-antimony-3 alloy has high mechanic integrity, good casting properties and it is used in printing, bearing production, and for different metal brazing. Alloys like lead-antimony-3 are used in the cable industry as means of rust-protection for underground and underwater data and power cables. Calorific capacity is a key property of substances, and its temperature-based changes can be used to determine the phase change type, Debye temperature, vacancy formation energy, electronic heat capacity factor, and other properties. This work presents the results of the experimental calorific capacity determination for the composition of lead-antimony alloys and calcium, and the calculation of temperature dependency of the changes of thermodynamic functions of alloys. The study of temperature dependency of lead-antimony and calcium composition calorific capacity was carried out in the “cooling” mode using computer hardware and Sigma Plot software. The polynomes were identified for the temperature dependency of calorific capacity and the changes of thermodynamic functions (enthalpy, entropy, and Gibbs energy) for the composition of lead-antimony alloy and calcium against the reference (Cu) that describe the changes using the correlation rate of Rcorr = 0.999. It was established that as the content of calcium in the composition increases, the calorific capacity decreases as compared to the initial alloy, yet it grows along with the temperature. The enthalpy and entropy of the lead-antimony-3 alloys and calcium compositions grow along with the temperature, while the Gibbs energy value decreases.