Preparation And Properties Of Yellow Pigments Based On Yttrium And Molybdenum

Inorganic yellow pigments with high thermal stability have always been a hot research topic in the field of materials.They can be widely used in ceramics,glass,exterior buildings and other areas for coloring and decoration.At present,the domestic market of ceramic pigment production has gradually changed from the growth and rapid development period to the stable development and maturity period.From now on,the main task is to improve the quality of the products and develop new products.In this paper,the optimum conditions of powder refinement during milling process are studied and the Y₄MoO₉ pigment is prepared by high temperature sintering.Then,Y₄MoO₉ is dopted by Zr/Ta/Tb/Bi element to determine the best process conditions,their structure and performance are determined by XRD,XPS,EDS,SEM,UV-vis-NIR and CIE 1976 L*a*b*color scales.Finally,the feasibility of Y3.8Zr0.2MoO9+δ yellow ceramic ink is examinated.It turns out that the newly developed yttrium-molybdenum yellow pigment is a good yellow inorganic pigment with high thermal stability and good color saturation.（1）The optimum conditions for refining the raw powder of yttrium-molybdenum yellow pigments by solid-state reaction route are as follows:deionized water is used as the ball milling solvent;the milling rate is 300 rpm/min;the mass ratio of raw materials,zirconium beads and deionized water is 1:2:1;the milling time is 6h.（2）Y₄MoO₉ yellow pigment with ideal crystal phase could be prepared by muffle furnace at 1400℃.The color value is:L*= 95.1,a*=-8.3,b*= 48.4.（3）Y₄MoO₉ pigment is dopted by Zr element and Y4-xZrxMoO9+g（0≤x≤0.8）are sintered at 14000℃ high temperature.Y3.8Zr0.2MoO9+δhas the optimum yellow value（L*= 93.1,a*＝-4.8,b*= 57.5）.The main crystal phase is Y₄MoO₉ with a strong acid and alkali resistance.Near infrared spectroscopy diffuse reflectance is about 90%and it could be used as energy-saving colorants for exterior building walls and roofs.（4）Y₄MoO₉ pigment is dopted by Ta element and Y4-xTaxMoP9+δ（0≤x≤0.4）are sintered at 1400℃ high temperature.Y3.9Ta0.1MoO9+δ has the optimum yellow value（L*= 91.7,a*＝-3.8,b*= 59.8）.The main crystal phase is Y₄MoO₉.（5）Y_4-xTb_xMoO_9+δ（0≤x≤0.05）are prepared at 1400℃ and their color is changed from greenish yellow to yellow and orange with increasing Tb doping amount.Besides,their main crystal phases are all Y₄MoO₉.（6）The best sintering temperature of Y4-xBixMoO9+s（0≤x≤0.05）is 1200℃.When x is 0.8,good orange color is obtained.L*a*b*is 78.1,10.2 and 45.6 respectively.The main crystal phase is the composition of Bi2MoO6 and Y6Mo012.（7）Y_3.8Zr_0.2MoO_9+δ yellow ceramic ink is prepared by dispersion method.The particle size is 0.923μm with narrow paticle size distribution.The viscosity is 0.381Pa.s.