Synthesis Of High Performance Sub-micron Zircon-based Pigments And Study On Enhancing Tinting Strength By Spectral Regulation

Zircon-based pigments have excellent physical and chemical properties such as high-temperature resistance,tinting strength stability,and strong acid and alkali corrosion resistance,which plays a critical role in the field of ceramic decoration.With the prevalence of inkjet printing technology,ultrafine zircon-based pigments have become the focus of industry research.Although the development of pigments for ink-jet printing has been going on for 20years,there are still many challenges,such as large particles of pigments,serious agglomeration,and the attenuation of color with the decrease of size,which cannot be directly used as pigments for inkjet printing.Therefore,in this work,sub-micron zircon and a series of ultrafine zircon-based pigments were synthesized under acidic and high-fluorine conditions,and the size reduction of zircon and the coloring mechanism of pigments were explored.The tinting strength limit of ideal yellow and red pigments are predicted,and the tinting strength of real pigments can be enhanced by three-light region regulation.Based on this,through ion compound doping,the significant enhancement of tinting strength of Pr–ZrSiO₄,Tb–ZrSiO₄,CdSSe@ZrSiO₄ are realized.In addition,the decomposition method of pigments was further discussed,and on this basis,the concept and calculation method of the encapsulation ratio of zircon-based pigments were established.The specific research is as follows:（1）Under acidic and high-fluorine conditions,the size of zircon was successfully reduced from micron（3–8μm）to submicron(D₅₀=312 nm),and sub-micron ultrafine powder with good dispersibility was obtained.Under high-temperature solid-phase conditions,the strong complexation of Zr-F weakens the Zr-O-Si binding ability,resulting in a significant reduction in the size of zircon.The zircon powder synthesized by the method has the advantages of small size,narrow particle size distribution,no agglomeration,etc.,and can meet the requirements of inkjet printing.（2）The synthesized sub-micron Pr–ZrSiO₄ yellow pigments has good dispersibility,the average particle size D₅₀ is 293 nm,and the yellowness value b^*reaches 17.57.The coloring mechanism of Pr–ZrSiO₄ yellow pigments was discussed in depth:innovatively synthesizing the pigments through different atmospheres,adjusting the ratio of Pr³⁺and Pr⁴⁺,and then confirming the coloring mechanism of Pr–ZrSiO₄ yellow pigments originates from the existence of Pr⁴⁺,that is,the charge transfer transition from O 2p to Pr 4f.For the first time,the spectral simulation calculation based on pigments was proposed,and the tinting strength limit of the ideal yellow pigments was predicted,b^*=145.40.The calculation of the real Pr–ZrSiO₄yellow pigments shows that the b^*of the sub-micron ultrafine pigments is expected to increase to 54.35 after the absorption enhancement in the extinction region and the optimization of the transition region.Based on the above calculation guidance,doped with Zn O in oxygen atmosphere,the absorption enhancement in the strong extinction region improves the tinting strength of the pigments,and the b^*increases from 17.57 to 32.02.（3）The coloring mechanism of sub-micron Tb–ZrSiO₄ yellow pigments was discussed after different atmosphere treatments(derived from the existence of Tb⁴⁺,that is,the charge transfer state from O 2p to Tb 4f)was further explored.By spectral calculation,it is predicted that the b^*of the real sub-micron Tb–ZrSiO₄ pigments is expected to increase to 68.45.Based on the above calculation guidance,by compound doping Ce O₂,the reflection of the strong high-reflection region is improved,thereby enhancing the tinting trength of the sub-micron Tb–ZrSiO₄ yellow pigments,b^*is increased from 21.67 to 23.37.（4）A sub-micron CdSSe@ZrSiO₄ red pigments with good dispersibility was synthesized,with D₅₀ of 0.78μm and red value a^*of 34.20.Compared with different commercial pigments,Cd_4.54S₄Se@ZrSiO₄ has better redness value（a^*=34.20）and higher saturation（C^*=38.71）.Furthermore,the tinting strength limit of the ideal red pigment is discussed.Under the condition of complete absorption in the strong extinction area and complete reflection in the high reflection area,the limit a^*of the red pigments can reach 80.51.For the color simulation calculation of the real sub-micron Cd_4.54S₄Se@ZrSiO₄ pigments,a^*is expected to increase from34.20 to 50.61.Guided by this calculation,Ta₂O₅ was introduced in this study to enhance the absorption in the extinction region,so that the a^*of this real sub-micron pigment actually increased to 42.47.（5）In order to realize the absorption enhancement of the extinction region of the pigment,it is proposed to increase the encapsulation ratio of zircon.Therefore,the decomposition of inert zircon was explored to explore the effect of the encapsulation ratio of zircon-based materials on its tinting strength.This work focuses on the regulation of the three-light area to enhance the tinting strength of sub-micron zircon-based pigments,which provides the theoretical guidance and basis for the improvement of existing pigments and the development of new pigments（fluorescent,photochromic,and pearlescent pigments）.