چكيده به لاتين
Nowadays, the wide range of applications for nanomaterials is no secret and one of important ones is their usage as nano pigments. In this thesis, hybrid nanostructures of ZnO and Co (CoxZn1-xO), a green pigment, were synthesized using combustion synthesis under microwave radiation. In this research, Taguchi design of experiment approach was employed to lower the number of required samples and systematically investigate the influence of variables involved in synthesis including fuel, cobalt percentage, fuel to oxidizer ratio and template (impregnated active layer). Three fuel types, i.e. xylitol, mannitol and sorbitol were used. The templates used to synthesize the nanopowder are filter paper, cotton and sterile gauze. In this study, the effect of fuel to oxidizer ratio at three levels of less, equal and greater than stoichiometry and also effect of cobalt doping with different percentages of 4, 7 and 10 on the structure of the ZnO network have been investigated. To characterize the materials, XRD, EDX, FTIR, FESEM, reflectance spectrometry and The CIE L*a*b* and CIE LC*ho tests were used. The optimized sample was synthesized under following conditions: mannitol fuel, filter paper, 7% cobalt, fuel/oxidizer ratio of 1.3St and calcination temperature of 400 °C. XRD spectra of this sample reveals only wurtzite phase of ZnO indicating that other phases are not existent in the structure. The optimum sample's crystallite size was ~35nm, which is about 3% different from the Taguchi prediction. FESEM images revealed the homogeneity of the nanoparticles, with average particle size of ~90 nm. The optimum sample has colorimetric parameters of L* = 58.19, a* = - 13.56, C* = 14.35 and h° = 162.07 and the best pigment was synthesized with xylitol fuel, filter paper template, 7% of cobalt and F/O of 1.3St which had colorimetric parameters of L*= 62.38, a* = - 16.76, C* = 17.74 and h°= 160.8.
