Synthesis and Study the Structural Characteristics of Cr2O3, CoCr2O4 and Al2O3-2Cr2O3 Ceramic Nano Pigments by Hydrothermal Method

Chromium oxide based nanopigments are widely used in many fields such as coating, wear and wear resistance materials, H2 absorbent material and advanced colorants. In this paper, chromium oxide-based nano pigments of Cr2O3, CoCr2O4 and Al2O3-2Cr2O3 were synthesized via hydrothermal method and then calcinated at 770 °C for 4 h. The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results of XRD analysis show that Cr2O3 and CoCr2O4 were crystallized in a single-phase structure while Al2O3-2Cr2O3 was crystallized in multi-phase structure. SEM images show that the pigments are nanostructures and the average particle size of Cr2O3, CoCr2O4 and Al2O3-2Cr2O3 nanopigments were about 57, 33 and 83 nm, respectively. The samples were also characterized by diffuse reflectance spectroscopy (DRS) and CIE-L*a*b* colorimetric measurement. The nanopigments obtained in this work presented different colors such as green and greenish yellow colors.