FORMATION OF NANOSTRUCTURED NiAl COATING ON CARBON STEEL SUBSTRATE BY USING MECHANICAL ALLOYING

Nanostructured NiAl intermetallics coatings were generated on carbon steel by using mechanical alloying in ambient temperature and pressure. Ni and Al powders were mixed with the composition ofNi-50 at% Al. The process involved powder particles trapped between the ball and cold welding atsurface. Coatings were examined using X-ray diffraction and scanning electron microscopy (SEM). The results showed that the phase transmutation during process and subsequent heat treatment are strongly affiliate on mechanically alloyed time. After 480 min heat treatment of mechanically alloyed sample, only NiAl peaks were viewed. Ball encounters and failures consecutive reduced the coarse grains of the coating to the nanoscale. The size of nanocrystalline grains in the NiAl coating ranged between 28nm to 130nm. The creation of the coatings was studied at milling intervals between 60 and 600 min. The average thickness and hardness of the surface layers at 480 min, were 470 μm and 930 HV, respectively.

کلیدواژه ها:

NiAl ، Coating ، Mechanical alloying ، Intermetallics ، Nanostructured materials