<p>This work examines the thermophysical and physicochemical characteristics of an electrode coating formulated from CaF₂, Al₂O₃, CaO, and SiO₂, intended for use in welding components in nuclear power plants. A total of 21 different flux compositions were developed using a mixture design approach to analyze the influence of flux mineral proportions on properties such as enthalpy change (∆<i>H</i>), thermal diffusivity, specific heat, thermal conductivity, and weight loss (∆<i>W</i>). These characteristics are important for achieving reliable and high-integrity weld joints. Structural analysis of the coatings was carried out through X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) to determine phase composition and bonding features. Thermal properties were evaluated using a hot disk technique, while thermogravimetric analysis (TGA) was used to assess weight loss behavior and enthalpy change. To understand the influence of individual components and their interactions, a regression model was developed. The results reveal that weight loss was positively affected by the presence of SiO₂, CaO, and CaF₂, along with a notable interaction between CaO and Al₂O₃. Enthalpy was mainly influenced by SiO₂ and CaF₂, whereas thermal conductivity was improved by the addition of Al₂O₃ and CaF₂ and their combined effects with SiO₂ and CaO. Thermal diffusivity is positively impacted by CaO and CaF₂, whereas specific heat is influenced positively by CaO, SiO₂, Al₂O₃, and CaF₂ but negatively by the interaction of CaO.Al₂O₃.</p> Graphical Abstract <p></p>