Using a plasma spray torch, nanocrystalline γ-alumina powder has
been synthesized in a reactor through oxidation of micron-size aluminum
metal powder by in-flight thermal plasma processing. The synthesized
particles were characterized by X-ray diffraction (XRD) and field emission
transmission electron microscopy (FE-TEM). The particle size was in the
range of ~7 to ~56 nm and spherical in shape. Furthermore the
nonlinear refractive and absorptive indices of the sample under various
intensities using Z-scan and moiré deflectometry techniques by a CW
He-Ne laser at 632.8 nm wavelength were measured.