The Preparation And Characteristics Of Novel Mica Titania Pearlescent Pigments With Thermal Stability

With excellent pearl luster,mechanical strength,weather resistance and innocuity,mica-based pearlescent pigments are widely studied and applied.They could sharply increase the value of mica mineral resources in our country.Therefore,the study of mica-based pearlescent pigments is significant for the high value-added utilization of mica mineral resources.However,current mica-based pearlescent pigments can barely resist high temperature above 1000?,which limits their application in special high temperature fields.How to enhance the thermal stability of mica-based pearlescent pigments becomes a meaningful task.Of all,the base material and the coating of oxide nanoparticles on mica are key factors which could lift high temperature resistance of pearlescent pigments.In this paper,mica titania pearlescent pigments were prepared by chemical deposition method,using fluorophlogopite and phlogopite as base materials.The effects of mica titania pearlescent pigments with different preparation factors and various titanium solution preparations were investigated using X-ray diffraction(XRD),scanning electron microscopy(SEM),whiteness and pearlescent effect analysis in detail.The results testify that the optimal preparation conditions of fluorophlogopite titania pearlescent pigments are the pH value 2,the solution temperature 85 ?,the reaction time 2h,the titanium solution concentration 3mol/L,the mole ratio of rutile promoting additive Sn4+ and Ti4+ 1:6,the sintering temperature 900 ? and the sintering time 1h.What's more,when titanyl sulfate solution is obtained by titanium tetrachloride dropping into 20%dilute sulphuric acid solution,the pearlescent pigments have better pearl luster than those which use titanium tetrachloride aqueous solution as deposition agent.Moreover,the effect on the pearlescent pigments' thermal stability of doping rare earth elements and the impact of different base materials were studied.The results indicate that doping Lat3+ would promote the pearlescent effects and high temperature resistance of the pigments.On the other hand,the pearlescent pigments which involve Ce3+ and Nd3-have poor pearlescent performance and thermal stability.In addition,the pearl luster of the phlogopite titania pearlescent pigments is better than that of fluorophlogopite titania pearlescent pigments.Muscovite titania pearlescent pigments don't have pearl luster as good as previous ones.And the pigments which use fluorophlogopite as substrate are more thermally stable than phlogopite and muscovite pearlescent pigments.The high thermal stability of muscovite pearlescent pigments is the worst.