Preparation And Properties Of New Nano-bismuth Vanadate Yellow Pigments

In this paper,nano-BiVO₄ yellow pigments were prepared by the method of precursor calcined and the ceramic method.On the basis of the method of precursor calcined,composite BiVO₄ yellow pigments were prepared by doping CaCO₃,CaF₂,Al(OH)₃,MgO respectively. Additionally,nano-BiVO₄ yellow pigments and composite BiVO₄ yellow pigments were charactered by using XRD,thermal analysis technology,FT-IR and electron microscopy analysis and so on.Using Bi(NO₃)₃·5H₂O and NH₄VO₃ as raw materials,BiVO₄ yellow pigments were prepared by the method of precursor calcined.The influence of reaction concentration,the value of pH,reaction temperature,reaction time,calcining temperature and calcining time on the crystal morphology,particle size,color and distribution were investigated,including the kind of and the dose of surfactants.Furthermore,the preparation conditions of calcining temperature,calcining time,rubbing and mineralizations which including the categories and the dose were studied the ceramic method.For this two methods,the coloring,thermal stability and infrared absorption properties of BiVO₄ yellow pigments were discussed.The results show that the monoclinic BiVO₄ yellow pigments with bright color,uniform distribution and the average size between 15nm and 30nm were obtained by the method of precursor calcined.And the dispersion of BiVO₄ yellow pigments can be improved by adding surfactant DBS.However,the monoclinic BiVO₄ yellow pigments with dim color,poor distribution and the average size between 40nm and 50nm were obtained by the ceramic method.The degree of the monoclinic BiVO₄ yellow pigments' crystallization was improved, and the particle size was smaller,and the color was changed at a certain extent by adding the mineralizations such as CaF₂ and H₃BO₃ through the ceramic method.Compared to the ceramic method,the BiVO₄ yellow pigments which were prepared by the method of precursor calcined have a brighter color.The BiVO₄ yellow pigments which were prepared by the two methods have a better thermal stability and have unconspicuous change of infrared absorption. BiVO₄ yellow pigments were modified by doping CaCO₃,CaF₂,Al(OH)₃,and MgO.The effects of different substance and substance with different concentrations on the crystal structure,thermal stability,color performance and infrared absorption of BiVO₄ yellow pigments were investigated.The researches show that composite BiVO₄ yellow pigments have a monoclinic crystal structure and a better thermal stability.And the BiVO₄ yellow pigments with different hues were prepared by doping different substance.The pigment color can be changed from yellow with a little red to yellow with a little green.Moreover,with the doping dosage increasing,the color performance has changed under the condition of doping same substance.