Synthesis Of Cobalt Blue Pigment And Its Ceramic Inks For Ceramic Ink-jet Priting

Today, ceramic inkjet technique attracts great attention from the Chineseceramic industry. Compared with traditional ceramic decoration technology, itrequires much higher standard in particle size distribution, mean particle size,morphology and dispersion for the ceramic ink. Therefore, there are nocommercial ceramic ink produced by Chinese manufacturer, and they aremainly imported from abroad.In this study, CoAl2O4spinel pigments were firstly prepared by solidphase synthesis, using cobalt oxide and alumina as raw materials. Thecolorimeter, XRD, SEM and micro spectrometer were used to investigate theeffect of reaction temperature, preservation time and the amount of moltensalt on the colorimetric results, reflection intensity, crystal morphology,particle size and crystallization. The results showed that the cobalt bluepigments sintered at1150°C for2h show the best Lab value(L=44.64,a*=-9.56,b*=-42.09) and reduced aggregation.Cobalt blue pigments were fabricated by self-propagating combustionand high temperature calcinations from xerogel precursor, which prepared bysol-gel method using Co(NO3)2·6H2O and Al(NO3)3·9H2O as raw materials.The colorimeter, XRD, SEM and micro spectrometer analysis were used toinvestigate the effect of metallic ion concentration, dispersants, pH value,reaction temperature on the formation of gel, it also studies the effect ofcalcinations temperature on colorimetric results, reflection intensity, crystalstructure and crystal size of CoAl2O4. The results showed that, i) the increaseof metal ion amount (0.01~0.1mol/L) and sol reaction temperature led to rapidgel formation; ii) the pH value around6.5is ideal for citric acid ionizationand complexation with metal ions; iii) the presence of dispersants couldimprove the agglomeration of cobalt blue pigment; iv) The CoAl2O4spinelstructure was able to be achieved after self-propagating combustion of xerogelprecursor and followed by high temperature calcinations at1250°C. Theparticle size of pigment is around200-600nm, the a*value, b*value andL*value is-8.73,-43.06and44.39, and the pigments are well dispersed.Blue ceramic ink was prepared by dispersion method, using the pigmentsproduced by previous solid phase reaction and sol-gel methods. In thissection,nanoparticle size potential analyzer, viscometer, surface tension meter,pH meter and UV visible spectrophotometer were selected to characterize the effect of grinding process, organic solvent and dispersant on the properties ofour developed ceramic inks. Research results indicate that the self-developedceramic ink is equal to the foreign commercial ink, after grinding2h andcontrolling the amount ratio of glycol and dispersant F (dispersant CH-13).