In the article, using the experimental data obtained in recent years on the contact angles and surface energies of solid copper and liquid indium, their interfacial energies are calculated at different temperatures. Knowledge of the interfacial characteristics is dictated by the need to obtain new materials that can operate under extreme conditions. For these and some other purposes in modern engineering and technology, they began, for example, to use high-vacuum brazing of high-temperature metal products using low-temperature metals and alloys. An important role in such processes is played by the interfacial energy at the solid-melt interface, which determines the contact angle: the lower the interfacial energy, the smaller the contact angle, and the smaller the contact angle, the better the processes of soldering, welding and liquid-phase sintering, etc. etc. Unfortunately, until now there is no direct method for measuring the interfacial energy. Therefore, the calculation of this value is an urgent task.
