Elevated temperature ablation resistance and thermophysical properties of tungsten matrix composites reinforced with ZrC particles

In order to improve the elevated temperature ablation resistance of the cop per infiltrated tungsten materials (Cu/W) which are used as the rudders of the rocket motors at present, a new kind of tungsten matrix composites rein forced by 30 vol% zirconium carbide particles (ZrCp/W) was developed, and t he elevated temperature ablation resistance and thermophysical properties o f the new materials were investigated. The values of the mass ablation rate and linear ablation rate of ZrCp/W were much lower than that of Cu/W, whic h indicated that the addition of ZrC particles in tungsten matrix remarkabl y increased the ablation resistance. Thermal thermochemical oxidation of tu ngsten and ZrC particles was the main ablation mechanism of ZrCp/W. A self- made dynamic responding multi-wavelength pyrometer was employed to measure the ablated surface temperatures and a thermal couple was employed to measu re the back surface temperatures. The important temperature curves of the a blated surface and back surface of the specimens were successfully detected online, which indicated that ZrCp/W has good thermal shock resistance. The present of ZrC particles in tungsten matrix remarkably decreased the therm al conductivity and thermal diffusivity of the ZrCp/W composites, which is very useful for increasing the elevated temperature ablation resistance of the composites. The excellent elevated temperature ablation resistance of Z rCp/W is attributed to the lower thermal conductivity, lower thermal diffus ivity, oxidation resistance and high melting points. The good properties of ZrCp/W makes it be suitable for the rudders for rocket motors instead of C u/W. (C) 2001 Kluwer Academic Publishers.