Physicochemical properties of the Al Fe 2.18 alloy with alkaline earth metals

The main patterns of change in heat capacity and thermodynamic functions (enthalpy, entropy and Gibbs energy) of the aluminum alloy Al Fe 2.18 with calcium, strontium and barium depending on temperature and amount of alloying component have been established. It has been shown that with temperature increasing, the heat capacity, entropy and enthalpy of Al Fe 2.18 alloy with alkaline earth metals increase, while the Gibbs energy of the alloys decreases. With an increase in the proportion of alloying component in Al Fe 2.18 alloy, the enthalpy and entropy increase, and the value of the Gibbs energy decreases. It has been found that with temperature increasing, the oxidation rate of Al Fe 2.18 alloy with calcium, strontium and barium in the solid state increases. The oxidation rate constant is of the order of 10-4 kg/m2∙s^-1. It has been defined that the process of oxidation of Al Fe 2.18 alloy with calcium, strontium and barium is described by a hyperbolic equation. Using the potentiostatic method in the potentiodynamic mode at a potential sweep rate of 2 mV/s, it was found that additions of alloying components up to 0.5 wt.% increase the corrosion resistance of the initial Al Fe 2.18 alloy on 25-35%. In this case, there is a shift in the corrosion potential of the initial alloy to the positive region, and the potentials of pitting and re-passivation - in the negative direction of the y-axis. In the transition from alloys with calcium to alloys with strontium and barium, a decrease in the corrosion rate of alloys is noted.