Ceramic nanomaterials from aqueous and 1,2-ethanediol supersaturated solutions at high temperature

Abstract

The aim of this study was the synthesis and physicochemical characterization of some nanosized hydroxides/oxides interesting in the field of ceramic materials with the aim of developing new materials for technological applications in the field of high-performance coatings. In particular, attention was focused on ZrO 2⋅ nH 2O, ZrO 2, Zn(OH) 2, ZnO, Al 2O 3⋅ nH 2O, and Al 2O 3. The synthesis was carried out in 1,2-ethanediol at 150–160 °C or in water at 90 °C at a high degree of supersaturation in order to achieved nucleation rate much greater than the growth rate. The obtained ZrO 2⋅ nH 2O, Zn(OH) 2, and Al 2O 3⋅ nH 2O particles were peptized to eliminate possible agglomeration and then calcinated at a suitable temperature to allow the formation of the corresponding anhydrous oxides. The synthesized particles were characterized by scanning and transmission electron microscopy, X-ray diffractometry, and differential thermal analysis coupled with thermogravimetry and Fourier transform infrared spectroscopy. The study showed that all the products can be obtained in the nanostructured crystalline form; ZrO 2 presented the interesting feature of different tetragonal/monoclinic ratios depending on the solvent used for the synthesis. Preliminary results on the potentialities of these ZrO 2 particles as agents for ultrahard coatings on ceramic surfaces were encouraging and very promising.