Improvement of Tribological Behavior of Ti-6Al-4V Alloy Using Nanostructured NbSi2 and NbSi2-Al2O3 Plasma Spray Coatings

摘要

Ti-6Al-4V alloys are widely used in aerospace industries because of their high specific strength. However, they have poor wear resistance. Plasma spray coatings were investigated as a way to improve the wear resistance of this alloy. In this paper, nanostructured NbSi2 and NbSi2-Al2O3 coatings were employed to enhance the tribological properties of Ti-6Al-4V. Atmospheric plasma spraying process was used for coating deposition. The structural transformation of coatings was examined by X-ray diffraction test. The pin-on-disk tribometer was used to carry out wear tests under dry sliding conditions and the worn surfaces and wear debris were examined by scanning electron microscopy , compositional analyses and microhardness tests. The tribological test results showed that for the investigated conditions, both coatings had satisfactory values of friction and wear resistance and they could be suitable candidates for Ti-6Al-4V material. Finally, it was concluded that NbSi2-Al2O3 nanocomposite coated sample showed maximum hardness and highest wear resistance.