the university of manchester (u.k.) collaborated with central south university (csu) in china on the design and fabrication of a new carbide coating that outperforms other high-temperature ceramics (uhtc) and could pave the way for hypersonic (mach five or above) travel, according to a report on the university of manchester website.

university of manchester research could lead to hypersonic travel on future aircraft.
(university of manchester)

the new carbide coating can withstand temperatures as high as 3,000°c. uhtc coatings protect the vehicle traveling at rates five times faster than the speed of sound from oxidation and ablation (extremely hot air removes surface layers from metallic materials).

the article explained, “so far, the carbide coating developed by teams in both university of manchester and central south university is proving to be 12 times better than the conventional uhtc, zirconium carbide (zrc). zrc is an extremely hard refractory ceramic material commercially used in tool bits for cutting tools.”

the coating was developed through a reactive melt infiltration (rmi) and reinforced with carbon-carbon composite. the rmi process greatly reduced the time needed to make the ceramic and the composite added strength and resistance to surface degradation.

professor ping xiao, professor of materials science at the university of manchester said, “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 research was recently published in nature communications. the abstract stated:

“ultra-high temperature ceramics are desirable for applications in the hypersonic vehicle, rockets, re-entry spacecraft and defence sectors, but few materials can currently satisfy the associated high temperature ablation requirements.

“here we design and fabricate a carbide (zr_0.8ti_0.2c_0.74b_0.26) coating by reactive melt infiltration and pack cementation onto a c/c composite. it displays superior ablation resistance at temperatures from 2,000–3,000 °c, compared to existing ultra-high temperature ceramics (for example, a rate of material loss over 12 times better than conventional zirconium carbide at 2,500 °c).

“the carbide is a substitutional solid solution of zr–ti containing carbon vacancies that are randomly occupied by boron atoms.

“the sealing ability of the ceramic’s oxides, slow oxygen diffusion and a dense and gradient distribution of ceramic result in much slower loss of protective oxide layers formed during ablation than other ceramic systems, leading to the superior ablation resistance.”