High temperature ablation resistance of ZrNp reinforced W matrix composites

For the purpose of improving the high temperature ablation resistance of tungsten-based materials, a new class of composites was fabricated using particulate ZrN as reinforcement. The high temperature ablation behavior of the composites was investigated using oxyacetylene torch. Three different volume contents (up to 30 vol.%) of ZrN were added to tungsten. It was observed that the addition of ZrN particles significantly enhanced the ablation resistance of the tungsten composites. Higher volume fraction of ZrN particles resulted in lower ablation rates. It was observed that ZrN particles, when exposed to the flame, formed a stable oxidation layer of ZrO2 on the surface of the sample. This layer prevents further damage to the tungsten matrix, thus resulting in lower ablation rates. The effect of ZrN reinforcement content on the thermal behavior of the tungsten-based composites was also investigated. Thermal conductivity of the composites was seen to decrease as a function of temperature and reinforcement content. Lower values of thermal conductivity are helpful in enhancing the elevated temperature performance of the composites.