Nanopowders produced from natural sources using the simple coprecipitation method

Nanopowders are defined as powders having a particle size less than 100 nanometers. Due to the specific surface effect, they have unique and different properties from powders with larger particle sizes. The quality of nanopowders extremely depends on the purity and homogeneity of the grain/crystallite size. These factors are associated with the complexity of how the nanopowders are prepared. Nanopowders are widely available in the form of ceramic compounds, which are generally oxides, carbonates, sulfates, and carbides. The metal-oxide ceramic nanopowders can be prepared by simple coprecipitation. This method not only can produce high purity nanopowders, but also with a relatively narrow crystal size distribution and unique morphology. Those are very crucial for any kind of application. To cite some examples, a number of nanopowder types have successfully been synthesized with potential applications as follows: Fe₃O₄ and BaFe₆O₁₉ (as magnetic materials, microwave absorbent, magnetic fluid and gel), SiO₂ (as fillers to enhance mechanical strength), and CaCO₃ (as coating for corrosive protection, food additives, cosmetics and drugs).