The thermodynamic and structural properties of Fe - based (Al-Fe and Fe-Si) alloys in their liquid states at different higher temperatures have been studied assuming the interaction parameters of R-K polynomial are linearly and exponentially dependent on temperature. It has been observed that artificial miscibility gaps (also called artefacts) appear in the thermodynamic and structural properties of the aforementioned alloys at high temperature when the interaction parameters are assumed to be linearly dependent on temperature. The artificial miscibility gaps or artefacts observed in the former case are eliminated when the interaction parameters are supposed to be exponentially dependent on temperature. This implies that the interaction parameters of RK-polynomial for liquid alloys vary exponentially at elevated temperatures.