A one-step route to carbon-carbon: fast, but the data is missing
Published
What JHU APL reports: the lab developed FAST CAR2, a way to make carbon-carbon, a heat-resistant thermal-protection material, in one step. It introduces a carbon-bearing material into a carbon-fibre scaffold and consolidates it in minutes with field-assisted sintering, which the release calls essentially a rapid, high-current pressing method, instead of the repeated densification cycles used today. A 1-inch cylinder took a few days, under a tenth of the conventional time, and the team then made several 6-inch cylinders and one 8-inch cylinder. Pores were micrometres wide, against up to about 1 mm in industrial carbon-carbon, and the samples passed high-velocity oxygen-fuel heat tests that the release calls on par with industry products. Why it matters for materials: the bottleneck in carbon-carbon is the slow, repeated step of filling pores with carbon. If one pressing can do it without hurting the microstructure at full part size, lead time and cost drop. That is a process claim, not a new material. Our take: the release shows no strength, thermal-shock or oxidation numbers against conventionally made carbon-carbon, does not name the carbon-bearing precursor, does not say which samples were heat-tested at what temperature or for how long, and describes density only as comparable, if not superior. Shuttle-type re-entry carbon-carbon is not used bare: our archive page for reinforced carbon-carbon, the Space Shuttle material, describes a silicon carbide outer coating against oxidation, and lists a multi-mission design maximum of 1811 K, with coating recession negligible below 1967 K in arc-jet tests (NASA TM-104792). Any new route will be judged against data like that. What we would watch: published mechanical and oxidation data, and whether 8-inch cylinders can become real parts. What numbers would convince you?