Chemical interactions between B4C and stainless steel at high temperatures

With a view to investigating the chemical interactions between B4C and type 304 stainless steel, the reaction couples of these two materials were isothermally annealed in the temperature range between 1073 and 1623 K. As a result of the chemical interactions, complicated reaction layers were formed at the interface of the reaction couple. To evaluate the reaction kinetics, the decrease in the thickness of stainless steel and the reaction layer growth were measured as a function of temperature and time. The overall reaction generally obeyed the parabolic rate law. Both a parabolic rate law constant and an apparent activation energy were determined. A discontinuity in the temperature dependence of the parabolic rate constants was found in the temperature range between 1473 and 1498 K. This corresponds to the formation of the liquid phase at the reaction interface.