AVS 53rd International Symposium
    Advanced Surface Engineering Friday Sessions
       Session SE1-FrM

Invited Paper SE1-FrM1
Coatings for Aero Engine Applications: Current Status and New Developments

Friday, November 17, 2006, 8:00 am, Room 2007

Session: Coatings with Enhanced Thermal Stability & MAX Phases
Presenter: C. Leyens, Technical University of Brandeburg at Cottbus, Germany
Correspondent: Click to Email
Increasing demands placed on the efficiency and performance of aero engine gas turbines have resulted in ever higher process temperatures; this requires high thermal stability of the materials systems applied. Also, with increasing temperatures, the lifetime of components becomes strongly affected by oxidation and hot corrosion processes that eventually limit the useful service temperatures. Therefore, coating systems have been developed that effectively protect gas turbine hardware against environmental attack and at the same time provide thermal insulation of the underlying superalloy component. In the cooler part of the engines, titanium alloys are used which might be complemented with the application of intermetallic titanium aluminides in the future which have a higher temperature capability. To date, no coatings for these material are available, however, current research is looking for adequate solutions. The present paper will review state-of-the art science and technology of coating systems for high temperature applications in the turbine part of aero engines. Here, thermal barrier coating systems are applied consisting of a duplex layer system which is comprised of a metallic bond coating and a ceramic top coating that provides thermal insulation. The paper will address currently used coating technologies and will deal with a number of materials-related aspects such as thermal conductivity of the ceramic coating, thermal stability, lifetime and failure. Current research for future materials systems with improved performance will be highlighted. Moreover, coatings development for titanium alloys and titanium aluminides will be addressed shedding light on an emerging field of new coating systems. Major emphasis is placed on the thermal stability of the coatings, their interaction with the reactive Ti-containing substrate and their effect on the mechanical properties of the component.