Oxidation of zirconium boride (ZrB₂) powder

ZrB₂ has excellent physicochemical properties for high temperature applications. It finds numerous applications in nuclear and non-nuclear industries viz. thermal protection system, high temperature electrode, molten metal containment systems, incinerators and ultrahigh structural application in aerospace. When ZrB₂ is exposed to oxidizing environment at high temperatures it oxidizes which will degrade its properties. Knowledge of the oxidation kinetics is essential for its use at high temperatures. Powdered sample of ZrB₂ was taken in a platinum crucible (70 μl capacity) and heated under a constant flow of oxygen 6 L h^-1 in a thermal analyzer (Mettler Toledo 851e). Non isothermal experiments were carried out by heating sample from 393 K to 1273 K at various heating rates viz. 1, 3, 5, 10, 15 and 20 K min^-1. Isothermal experiments were carried out at pre-determined temperatures viz. 950, 970, 1010, 1030, 1050 and 1070 K (based on measurable mass gain observed after 900 K in the non isothermal experiments) for 600 min or till measurable change in mass was observed. Products of oxidation were characterized by using x-ray diffraction technique