Abstract
Abradable seals are used in compressors of aircraft and industrial gas turbines to decrease clearance between the stator casing and rotor blade tips and hence to increase compressor efficiency and decrease fuel consumption. The main interest of abradable materials producers has been concentrated on abradable seals for aircraft engines, and special requirements of industrial gas turbine manufacturers have not been met so far. The most significant requirement in industrial gas turbines is durability. This is driven by the need for several times longer periods between overhauls in industrial gas turbines compared to aircraft engines. Westaim Ambeon has developed a new composite powder, Durabrade2413, that meets these requirements. The new abradable seals fabricated by using this powder have been extensively tested over a prolonged period of time. This paper will present the results of an intensive development, evaluation and abradability testing of seal properties. This paper will also show that Durabrade2413 series coating properties can be altered in a broad range by changing spray parameters to tailor the coating to a particular application. The abradable seals are suitable to rub against steel and Ni alloy blades. The abradability results of Durabrade2413 are compared to Durabrade2222 (the Metco 307-NS equivalent), the well known 75Ni25 Graphite abradable that has been on the market for the last 30 years.
