When travelling at hypersonic speeds, the heat generated can threaten the structural integrity of aircraft as temperatures soar to between 2,000 and 3,000°C.
Until now ultra-high temperature ceramics (UHTCs) developed to provide protection for craft and projectiles travelling at five times the speed of sound (Mach 5) or above have not been sufficiently effective.
However, a carbide coating developed by researchers at the University of Manchester and Central South University (CSU) China is proving to be 12 times better than conventional Zirconium carbide (ZrC), an extremely hard refractory ceramic material commercially used for cutting tools.
Professor Philip Withers, Regius Professor from The University of Manchester, said: “Future hypersonic aerospace vehicles offer the potential of a step jump in transit speeds. A hypersonic plane could fly from London to New York in just two hours and would revolutionise both commercial and commuter travel.
“But at present one of the biggest challenges is how to protect critical components such as leading edges, combustors and nose tips so that they survive the severe oxidation and extreme scouring of heat fluxes at such temperatures cause to excess during flight.”
Research leader, Ping Xiao, Professor of Materials Science at the University of Manchester, explains: “Current candidate UHTCs for use in extreme environments are limited and it is worthwhile exploring the potential of new single-phase ceramics in terms of reduced evaporation and better oxidation resistance.
“In addition, it has been shown that introducing such ceramics into carbon fibre-reinforced carbon matrix composites may be an effective way of improving thermal-shock resistance.”
The improved coating performance is due to its unique structure and features, which include extremely good heat resistance and massively improved oxidation resistance.
The material was made at the Powder Metallurgy Institute, Central South University, using a process called Reactive Melt Infiltration (RMI). This reduced the time required for its manufacture and the material has also been reinforced with carbon–carbon composite (C/C composite), making it and extremely resistant to the usual surface degradation.