This study aims to investigate the physicochemical and thermophysical behavior of the electrode coatings produced using CaO-CaF2-SiO2 and CaO-SiO2-Al2O3 ternary phase systems. Electrode coating compositions for welding power plant materials are either patented or not available in the public domain so researchers need to explore the flux coatings to improve the properties of welds produced. An extreme vertices design methodology was used to obtain the different flux combinations to study the effect of electrode coating constituents on weight loss, density, specific heat, change in enthalpy, thermal diffusivity and thermal conductivity. These properties play an important role in achieving better weld quality. X-ray diffraction and Fourier-transform infrared spectroscopy techniques were used to analyze the different phases present and their structural behavior. Multi-response optimization was carried out to obtain the optimum flux composition and study the effect of individual constituents and their interaction effects on the thermophysical and physicochemical properties. © 2019, The Minerals, Metals & Materials Society.