Thermodynamic descriptions of the ternary Fe-B-V system and its binary sub-system B-V, are developed using experimental thermodynamic and phase equilibrium data from the literature. The thermodynamic parameters of the other binaries, Fe-V and Fe-B, are taken from earlier assessments slightly modifying the Fe-V description. The work is in the context of a new Fe-B-X (X = Cr, Ni, Mn, V, Si, Ti, C) database.

The solution phases are described using substitutional solution model. The borides are treated as stoichiometric or semi-stoichiometric phases and described with two-sublattice models.

This work concerns measurements of the radiant intensity emitted by LEDs. The influence of selected factors and parameters on the final measurement result are discussed. The research was conducted using two type of detectors: light meter and CCD camera, to compare the degree of influence of these parameters depending on the measurement instrument used.