Combustion synthesis: a new route for repair of gas turbine components—achievements and perspectives for development of SHS rebuilding

Repair techniques such as brazing diffusion remetalling (BDR) are extensively and successfully used in the aeronautical industry to extend the life of damaged turbine blades. Nevertheless, the development of new repair processes able to generate a reduction of costs and/or of the duration of the treatment cycles is a permanent objective. The basic advantages of the repair process based on the self-propagating high-temperature synthesis (SHS) are the rapidity, the self-generation of energy, the local treatment of the turbine component and the reduction in temperature by turbine component. This process ensures similar mechanical properties as traditional processes or at least sufficient for some applications. The purpose of this paper is to explain the principle of the SHS build-up process and through some examples to show the possibilities and the economical advantages offered. The build-up of a turbine blade tip and the simultaneous synthesis and joining of a NiCrAlY layer to a superalloy substrate are described.