Sintered silicon nitride (SSN) was advantageously applied for turbocharger rotors owing to its light weight and excellent high temperature strength, which would provide a better response and a high temperature capability.
SSN rotor have been fabricated by injection molding, sintering, machining, balancing and inspecting processes. Rotor construction could be shaped either monolithically or by bonding the turbine wheel with shaft.
Cold and hot spin testing have been carried out.
The highest tip speed observed was 580 m/sec at 750°C without failure.