THERMODYNAMICS OF THE SYSTEM ZR-B-H-CL - A CONTRIBUTION AT LOW-TEMPERATURE

A thermodynamic study of the Zr-B-H-Cl system was made at low temperat ure (800 to 1500K) and low pressure (1 to 100 mbar) by minimising of t he total Gibbs free energy of the system. The Zr-B phase-diagrams show ed that ZrB2 is the main solid product formed. The ZrB2 yield can reac h 100% under conditions of elevated temperature, high H-2 concentratio ns, and at low pressures. At low H-2 concentration, the addition of he lium had the same effect on the system as a reduction of the system's total pressure. The analysis showed that the system is controlled by t he formation of an intermediate species resulting from the reaction of H-2 with BCl3.