The Effect of Linear Speed on the Wear Behavior of TC4 Blade and Ni-G Seal Coating

The rubbing behavior between compressor's blade tip and seal coating was simulated through a high speed rubbing test rig. The wear behavior of TC4 (titanium alloy) blade and Ni-G (nickel-graphite) seal coating under linear speed varying from 30 m/s to 150 m/s was studied. The wear mechanism of the rubbing system was studied based on the results from scanning electron microscopy, energy dispersive spectroscopy and X-ray photoelectron spectrometer of the wear scar of the blade tip and the seal coating plus the vickers microhardness test of the coating's wear scar surface. The results reveal that with the increase of the linear speed, the wear rate of the blade firstly increased, then decreased. At low linear speed, thanks to the severe densification of the coating, the wear of the blade was mild. The rubbing between the blad and the coating wear scar's transfer layer of which the microhardness was high resulted in significant wear of the blade at medium speed. At high speed, the thick oxide layer on the blade tip prevented the transferring to the coating from the blade and the wear of the blade was mitigated.