Synthesis And Characterization Of Pr-ZrSiO₄ Ceramic Pigment

The praseodymium zircon yellow ceramic pigment is one kind of interstitial solid solution with zircon substrate, the pigment with the prominent high chemical durability, strong coloring, the perfect corrosion resistance and the ability of resistance to glaze melt is used widely for mass coloration of many materials including glazes, ceramic bodies and porcelain enamels. Moreover, it’s the only option for preparation of the praseodymium zircon yellow ceramic ink at present. However, the properties and preparation procedures of praseodymium ziron yellow pigment should be further improved.The praseodymium zircon yellow ceramic pigment were synthesized by using a chemical co-precipitation method in the experiment, The main influential factors affected the performance of the pigment such as preparation methods of precursors, pH of mixture solution, the type and dosage of mineralizer, the ratio of Zr against Si, the soluble salt content, the addition amount of Pr6O11, the dosage and varieties of dispersant and calcination processes were investigated. The pigment powders were characterized by SEM, XRD, TG/DSC, the CIE L*a*b* parameters measurement and particle size analyzer. The results show that the best performance of the praseodymium zircon yellow pigment has been achieved when the mass ratios of ZrOCl2·8H2O against sodium silicate is 8.5 : 6, the molar ratios of Zr against Pr6O11 is 1 : 0.01, m( ZrOCl2·8H2O) : m( NaF) : m( NH4Cl) = 3.4 : 0.16 : 0.33, and pH of mixing solution should be adjusted to10.0. Additionally, the synthesized powders should be calcined at 900℃ for 2 hours. Moreover, the dispersant is the important factor to prepare the pigment with excellent performance. Polyvinylpyrrolidone( PVP K30) is a nice choice for the reaction system, and the addition amount is 1.0% of the theoretical yield of zircon.After treatment at 1100℃, the CIE L*a*b* parameters of the pigment powders prepared according to the above conditions are L*=84.04, a*=0.22, b*=74.21, respectively. d50 and d96 of the pigment powders are 0.352 μm, 1.096 μm, respectively after milling in the deionized water with some appropriate dispersant, and the CIE L*a*b* parameters are L*=88.70, a*=-5.02, b*=59.52, respectively. Furthermore, the CIE L*a*b* parameters are L*=88.18, a* =- 6.47, b*=43.88 when d50 and d98 decrease into 0.193 μm, 1.096 μm, In this case, the pigment has good particle size distribution and displays a bright yellow color.