Thermodynamics of TiN Formation in Fe-Cr Melts

Abstract

The equilibrium solubility of titanium and nitrogen in Fe-Cr melts was measured in the presence of pure solid TiN under various nitrogen pressures. The activity coefficients of titanium and nitrogen relative to 1 mass% standard state in liquid iron were calculated from the experimental results in the temperature range of 1 843-1923 K. The first and second order interaction parameters of chromium on titanium and nitrogen were determined as a function of temperature. The validity of thermodynamic parameters determined in the present study was examined by constructing the stability diagram of TiN for Fe-Cr melts and by observing the formation of primary and secondary TiN inclusions at controlled titanium and nitrogen contents in the melt.