High-temperature reaction of oxygen-stabilized α-Zr(O) with nitrogen

This paper presents for the first time results of the reaction between oxygen-stabilized α-Zr(O) and nitrogen. This reaction plays an important role during air oxidation of zirconium and its alloys. A wide range of temperatures (1073-1673 K) and composition of the α-Zr(O) phase (1.5-6.5 wt.% oxygen) was investigated in thermo-gravimetric experiments. The reaction is of linear kinetics and much faster than the reaction of the oxygen-free metal (alloy) with nitrogen. Strong dependencies on temperature and initial composition of the α-Zr(O) were found. The reaction kinetics becomes faster with increasing temperature up to 1470 K before it slows down with further rising temperatures. The strong dependence on the oxygen content in the metal could be best described by a fourth root correlation of the linear reaction rate constants.