Influence of 1 and 5 wt% TiC additions on the oxidation behaviour of pure tungsten

Abstract

• The amount of the TiC additions strongly depends on the oxidation behaviour of W. • Low TiC additions greatly reduce oxidation kinetics at 700 °C compared to pure W. • A low TiC content inhibits massive microcracking events occurring in pure tungsten. • A high TiC content accelerates the oxidation rate. The influence of 1 and 5 wt% of TiC nanoparticles on the oxidation behaviour of reinforced tungsten has been evaluated up to 700 °C in dry air. Isothermal thermogravimetric tests prove that the addition of 5 wt% of TiC particles is detrimental, increasing the mass gain of pure tungsten by a factor of ten. TiC particles act as stress concentrators, facilitating microcracking events within the scale and promoting decohesion between TiC-free boundaries and TiC-containing regions of the material. Compared to pure tungsten, lowering TiC addition to 1 wt% significantly improves the oxidation resistance at 700 °C by reducing about seven times the mass gain, while at 600 °C both materials exhibit similar resistance. At 700 °C, the presence of 1 wt% of TiC particles inhibits massive microcracking events occurring in the scale formed on pure tungsten, rendering the oxide scale denser and more protective.