Lycoming wrote:The main con is that ceramics are still very brittle. Jet engine turbines are still inconel. Not quite the same as the turbine on a turbo, but still quite similar.
Jet engines are much different than road engines. An aircraft doesn't stop on the side of the road when something inside an breaks down. It usually crashes and people may die. So incanel turbine blades have a solid place there.
This year F1 makes turbine explosion particularly dangerous for following cars due to rules prescribed exhaust pipe exit straight back from turbo. As such, the ceramic turbine wheel would go in some ways to increase the safety margin in risky situation.
http://www.jsae.or.jp/autotech/data_e/12-5e.html
https://www.memsnet.org/material/siliconcarbidesicbulk/
Ceramics are brittle, however this application is not new for silicon carbide and since it was used by Nissan in OEM application, the technology is mature to be used in motorsports if rules permit it. Density comparison:
- inconel - 8.4 g/cm^3
- SiC - 3.2 g/cm^3
Clearly, the reduced rotating inertia for turbo lag related characteristics is favorable, as well as the burst energy aspect that must be contained. On top of that , when such ceramic part fails and bursts, it rather pulverizes into much less harmful powder than tough inconel blades.