Hydrophilic (polar-P) and hydrophobic (apolar-A) SiO2 nanoparticles were used as assistant materials to improve the fluidizability of Al2O3 and TiO2 nanopowders, which are hard to fluidize normally. To decrease the strong electrostatic forces, binary mixtures prepared with SiO2(P) were fluidized in the presence of suitable alcohol vapors. Results showed that the amount of SiO2 nanoparticles, varying from 5 to 50wt%, mostly had a beneficial effect on the fluidization quality of the binary mixtures in both cases. TiO2 and Al2O3 nanoparticles combined with 20 wt% SiO2(A) showed almost equal performance in terms of fluidization with the mixtures containing only 5 wt% SiO2(P). This behavior can be addressed by better material homogeneity of latter mixtures which led to a homogeneous, smooth and stable behavior with desirable bed expansion. By comparing the results obtained in this work with those available in the literature, it is proposed that physical mixing with SiO2(P) NPs to improve the flowability of Al2O3 and TiO2 hard-tofluidize nanoparticles, may be comparatively more efficient than even some of the external methods such as acoustic field or mechanical vibration.