The Preparation And Characterization Of Mica/Composite Oxide Pearlescent Pigments

In this paper, it was prepared by precipitation method to coat composite oxide onto mica, such as titanium cobalt green and cobalt chromium green composite inorganic oxide, Thermogravimetric differential thermal analysis (TG-DSC), X-ray diffraction (XRD), Atomic force microscope (AFM), Scanning electron microscopy (SEM) and CIE L*a*b* methods were characterized were employed to characterize the morphology of the mica composite particles, and the major work is summarized as follows:It was prepared by precipitation method to synthesize mica/titanium cobalt green pearlescent pigment, The effects of the calcination temperature, mole ratio, the coating rate, different size of mica, pre-treated and sort of doping ions on the crystal structure and colorimetric characters of compound pigment. TG-DSC analysis and XRD patterns analysis showed that the appropriate calcination temperature for mica/Co2TiO4 pigments was about 1000 ℃. SEM and AFM were employed to characterize the morphology of the composite particles, they showed that mica were coated uniformly with a single layer of dispersed composite oxide particles. The Ti/Co mole ratio had some effects on crystal structure and color of their product compositions, as Co2+ dosage increased, the intensity of the spinel characteristic diffraction peaks of Co2TiO4 got strengthen, and the color of pigments deepen. For doping Ni2+, Zn2+. Mg2+, Cu2+, Mn2+,the Bragg reflection (311) shifts increased and lattice parameters were all decreased. Ni2+ and small Zn2+ doping dosage doping can improve the color and shading power of the doped pigments, while larger Zn doping dosage can weaken the color properties of the pigments. Doping with Mg2+, Mn2+ and Cu2+ metal ions can also weaken the color and shading power of the doped pigments.It was prepared by precipitation method to synthesize mica/cobalt chromite green pearlescent pigment, The effects of the calcination temperature, mole ratio, the coating rate, different size of mica and sort of doping ions on the crystal structure and colorimetric characters of compound pigment. XRD patterns analysis showed that the appropriate calcination temperature for mica/CoCr2O4 pigments was about 800℃. SEM showed that composite nanoparticles were scattered around mica particles, there is no form dense film on mica surface with the expected coated effect, modify code to experiment with coating titanium dioxide onto mica surface, coated chromium cobalt onto mica/TiO2. SEM was employed to characterize the morphology of mica/TiO2, they showed that mica were coated uniformly with a single layer of dispersed TiO2, mica/TiO2 were coated uniformly with nearly spherical particle with slightly superior to size of TiO2 particles, it explained cobalt chromium green composite particle deposited on the mica titanium, the experiment scheme is effective. The Co/Cr mole ratio had some effects on crystal structure and color of their product compositions, as Cr3+ dosage (Cr:1.8-2.2) increased, the intensity of the spinel characteristic diffraction peaks of CoCr2O4 got strengthen, and the color of pigments deepen. The lightness of larger size mica based pigment decreased, coating rate affected Lab values of mica pearlescent pigment. For doping Ni2+, Zn2+, Mg2+, Mn2+, Ca2+, Fe3+, Al3+, the Bragg reflection (311) shifts increased and lattice parameters were all decreased, doping with metal ions can weaken the color and shading power of the doped pigments.