Cold Spraying of Intermetallic Thermal Barrier Coating for Diesel Engines

Conventional thermal barrier coating (TBC) systems consist of a duplex structure with a metallic bondcoat and a ceramic, heat-isolative topcoat. Several recent research activities are concentrating on developing improved multilayer  bondcoat-TBC  materials; for the Al based bondcoat especially, those with reduced thermal conductivity are investigated. Using alternative TBC materials, the intermetallic layers can be further optimized to achieve the best thermal physical parameters. One example is the six-layer system in which  cold sprayed Al based intermetallics are synthesized . These systems demonstrated an improved temperature capability compared to another alternative TBCs. The microstructures and properties of the coatings were characterized by SEM, TEM and micromechanical tests to define the structure formation mechanisms. Application prospects for Low Heat Rejection (LHR) Diesel engines are discussed. The energy of the biodiesel can be released more efficiently with the concept of LHR engine with TBCs.