Hypersonic travel, which entails moving at least five times faster than the speed of sound, is a heat-intensive process. An aircraft moving at Mach 5 or greater is exposed to temperatures of 2,000° C to 3,000° C (3,632° F to 5,432° F), which can undermine structural integrity.
Ultra-high temperature ceramics (UHTCs) are needed to combat ablation and oxidation in aero-engines and hypersonic vehicles such as rockets, re-entry spacecraft and defense projectiles. Researchers from China and the UK have engineered a new carbide coating that is vastly superior, relative to existing UHTCs, in resisting temperatures up to 3,000° C. The zirconium-titanium-carbon-boron coating is proving to be 12 times better than the conventional UHTC, zirconium carbide, an extremely hard refractory ceramic material commercially used in tool bits for cutting tools.
Excellent heat and oxidation resistance are imparted by a reactive melt infiltration process and pack cementation onto a carbon-carbon composite. The sealing ability of the ceramic’s oxides combined with slow oxygen diffusion result in much slower loss of protective oxide layers formed during ablation.
Researchers from Central South University (Changsha, China) and University of Manchester (UK) participated in this research.