Ablation-resistant carbide Zr<sub>0.8</sub>Ti<sub>0.2</sub>C<sub>0.74</sub>B<sub>0.26</sub> for oxidizing environments up to 3,000 °C.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 28613275.
- Also identified by DOI 10.1038/ncomms15836 and PMC identifier 5474735.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
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<sub>0.8</sub>Ti<sub>0.2</sub>C<sub>0.74</sub>B<sub>0.26</sub>) 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.