Characterization of MCrAlY/nano-Al_(2)O_(3) nanocomposite powder produced by high-energy mechanical milling as feedstock for high-velocity oxygen fuel spraying deposition

Al_(2)O_(3) nanoparticles and MCrAlY/nano-Al_(2)O_(3) nanocomposite powder(M=Ni,Co,or NiCo)were produced using high-energy ball milling.The MCrAlY/nano-Al_(2)O_(3) coating was deposited by selecting an optimum nanocomposite powder as feedstock for high-velocity oxy-gen fuel thermal spraying.The morphological and microstructural examinations of the Al_(2)O_(3) nanoparticles and the commercial MCrAlY and MCrAlY/nano-Al_(2)O_(3) nanocomposite powders were investigated using X-ray diffraction analysis,field-emission scanning electron microscopy coupled with electron dispersed spectroscopy,and transmission electron microscopy.The structural investigations and Williamson-Hall res-ults demonstrated that the ball-milled Al_(2)O_(3) powder after 48 h has the smallest crystallite size and the highest amount of lattice strain among the as-received and ball-milled Al_(2)O_(3) owing to its optimal nanocrystalline structure.In the case of developing MCrAlY/nano-Al_(2)O_(3) nanocompos-ite powder,the particle size of the nanocomposite powders decreased with increasing mechanical-milling duration of the powder mixture.