Preparation Process Of ZrSiO₄/Cd(S_xSe_1-x)Inclusion Pigment By Sol-nucleation Method

Cadmium sulfoselenide, Cd(SxSe1-x), is an important ceramic pigment, with bright color change from yellow to red and strong tinting strength. While, its thermal stability is poor, when the temperature higher than 600oC, it is extremely easy to be oxided and decomposed, severely limiting the scope of application. Zirconium silicate(Zr Si O4) crystals are transparent and featured with strong resistance to chemical corrosion, allowing non-reaction with the pigments. By encasing Cd(SxSe1-x) of zirconium silicate, the Zr Si O4/Cd(SxSe1-x) inclusion pigment with good thermostability and excellent color rendering, can be thus produced. In this paper, a novel method named “sol-nucleation” is proposed to prepare Zr Si O4/Cd(SxSe1-x) inclusion pigment. In this process, the monodisperse Cd(SxSe1-x) nucleus is synthetised at first, then add it to the pre-prepared Zr O2/Si O2 composite sol, control the reaction conditions to make Zr O2/Si O2 composite sol uniform wrapped in Cd(SxSe1-x)nucleus, then Zr Si O4/Cd(SxSe1-x) inclusion pigment is synthesized at 700oC successfully.The effects of reaction temperature, p H value and zirconium silicate concentration on the stability of Zr O2/Si O2 composite sol were investigated and obtained the optimum experimental conditions for the existence of the composite sol stability. The optimum conditions obtained are as follows: the stirring speed of 1200 r/min, the solute content 15%, n(Si):n(Zr) ratio 1.5:1, p H 4 and temperature 55oC. Using the stable composite sol under above conditions, Cd(SxSe1-x) is successfully encapsulated by Zr Si O4, forming Zr Si O4 /Cd(SxSe1-x) inclusion pigment with high crystallinity and hues.Meanwhile, the effects of Na2S、Se and Cd SO4 content, p H and temperature on the color of the pigment were studied, as well as the effects of different dispersant and its dosage on the dispersibility of Cd(SxSe1-x) nucleus. The optimum conditions obtained are as follows: p H 13, temperature 75oC, n(S):n(Se):n(Cd) ratio 1.23:0.19:0.5 and used CTAB as the dispersant.The composite sol was characterized by XRD、SEM、TEM、IR, etc. This showed that, the average size of particles was 100 nm, and its main compontents was rad Cd(S0.571Se0.429).Zr Si O4 /Cd(SxSe1-x) inclusion pigment was prepared by sol-nucleation method of Cd(SxSe1-x) nucleus and Zr O2/Si O2 composite sol. When Zr Si O4/Cd(SxSe1-x) ratio 1.5:1 and used CTAB as the dispersant, Zr Si O4/Cd(SxSe1-x) inclusion pigment is synthesized at 700oC successfully. Result of TG、XRD、SEM、TEM、IR, etc. showed that, the particle of the pigment in this way is between 3-5μm, which high-temperature stabillity was up to the standard of the ceramic pigment.The sol-gel nucleation method has advantages of low synthesis temperature, simple process, low cost and the products with good dispersibility and fine particles, showing good prospect of industrial application.