Thermal Spraying of Aluminium Cylinder Bores by the Ford PTWA Spray Process

One of the main drivers in the automotive industry is the reduction in fuel consumptions and emissions. In order to achieve these goals, the weight of the engine block as well as the friction in the cylinder bore has to be optimized. This paper describes the FORD PTWA (Plasma Transferred Wire Arc) thermal spray process that protects the aluminum cylinder bore surface against wear by a thermal spray coating. The PTWA technology was originally developed for the application in gasoline V8 engines and it will be shown in this paper how this process can be modified to apply nano-material to produce high-wear resistant, low-friction coatings for highly loaded engine blocks for future demands. A large German BMBF “Nanomobile” Research Program was started in 2005 with 13 partners (DaimlerChrysler, Opel, Porsche, Ford, Gehring, Federal Mogul, GTV Thermal Spray Systems, DURUM, RWTH University and other institutes) in order to develop next generation nano-material coatings for cylinder bores.