Abradable
Derived from aero engine gas turbine compressors, these abradable and rub tolerant coatings are now applied to automotive engine turbochargers, pumps and compressors to provide clearance control. A turbocharger rotor spins at high speed within its housing. As its rotational speed increases, and to some extent the operating temperature, the outside diameter of the rotor also increases. If the clearances between the rotor blade tips and its housing were designed for optimal aerodynamic performance, this growth would cause the rotor blade trips to touch the bore of the housing. These clearances are therefore larger than desirable due to mechanical considerations.
Abradable clearance control coating applied to rotor path of turbocharger
The thermal spray coating solution for this problem is to apply a soft abradable coating to the housing bore that can be rubbed away by the rotor blades without causing material loss from the rotor. These coatings reduce the risk of blade damage and at the same time improve the efficiency and performance of the turbocharger by managing the rotor path tip clearance
Abradable Coating Features/Benefits
Raise Levels of Reliability
Lower Cost of Overhaul
Increase fuel Efficiency
Increase Performance
Low Material Transfer
Coating Wear without Surface Deformation
Low Adhesive Transfer
Low Turbine/Rotor Wear
Typical Applications
Turbochargers
Land Based Turbines
Aerospace Power Units<
Compressors
Pumps
Processes
Typical Materials
Aluminium-Polymer
Nickel Graphite
CoNiCrAlY-BN-Polymer