Abstract:
Micron sized metallic zinc dust (99.9%, Davg = 40 lm) was mechanically milled to have zinc oxide seed
nuclei on its surface, eventually transforming it into ZnO nanostructures by microwave irradiation for
15 min. Effect of milling on the growth of seed layer, oxidation kinetics, particle size distribution, nano
ZnO morphologies, phase purity, dispersion and UV absorption properties were studied and reported.
ZnO rods with length 5–6 lm and diameter of nearly 200 nm were successfully synthesized in bulk
through this facile route. The products were systematically characterized and studied with the motive
to design multifunctional nano-products. A paint formulation was made by blending the assynthesized nano ZnO with a natural organic resin; cashew nut shell liquid (CNSL) and surface coatings
were developed over glass and metal substrates. ZnO–CNSL paint coatings were further studied for
NIR reflectance, optical transparency and hydrophobic surface property. Its effective corrosion resistance
has been validated with highly corrosive Mg-alloy substrates, an upcoming key material for automobiles.
The ZnO–CNSL paint developed showed about 33% enhancement in NIR shielding and about 156%
improvement in corrosion resistance when compared to their uncoated counterparts. The study strongly
recommends microwave accelerated oxidation as a technologically competent process for the bulk
preparation of multifunctional nano ZnO.
