The wear, deterioration and transformation phenomena of abradable coating BN-SiAl-bounding organic element, caused by the friction between the blades and the turbine casing

In modem design of gas turbines, the use of abradable materials for the coating seal of engines is widespread. Indeed, in order to increase efficiency of gas turbines, clearances between rotating blades and the casing should be as small as possible. Therefore, the blades scrape this BN-SiAl seal to form a minimum gap. The aim of this work is to investigate the behaviour of a particular abradable material, the BN-SiAl-bounding organic element, during interreaction with the blades under experimental conditions of operating the rotor blade. For this purpose, we use a Sulzer Metco abradability test. Tests are made with different incursion speeds of blade within the coating seal as well as linear blade velocities. The obtained results are shown in the form of graphs describing how the transfer of coating wear occurs and the different effects are observed on the coating surface. (C) 2004 Elsevier B.V. All rights reserved.