| Inorganic functional materials are a large class of innovative materials that have special electricity, magnetic, optical, acoustic, thermal, stamina, chemical and biological function. Accompanied by the continuously development and improvement of micro-nanometer technology, inorganic functional materials have become a novel material subject which is based on micro-nanometer technology and micro-nanometer materials. There are many versatile types between inorganic functional materials. They are widely applied to information technology, biotechnology, energy technology, transport, environmental protection, national defense construction, and so on. Inorganic functional materials come into being a very broad industrial cluster, which possesses much expansive market prospect and very important strategic significance. At present, there are many preparation methods for micro-nanometer materials. It is a ubiquitous problem that the particles reunite easily and can not be preserved expediently. Researchers have made a lot of work to control reaction conditions, such as pH value, reaction temperature, adding additives, which have obtained a great deal of improvement methods. However, these methods are not applied universally for the rigorous reaction conditions, greater technical difficulties, high material quality demands, and large lump sum investment. To solve this problem, it is necessary to develop some novel methods. In this paper, we report a high temperature ball milling method with many advantages such as simple preparation process, lower cost, excellent products and easy industrial production. Compared with polyacrylamide gel method and chemical precipitation method etc, the related materials were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), ultraviolet visible spectrophotometry (UV-Vis) and excitation-emission spectra on structure, morphology and properties. The major work and research results are as follows:Firstly, nanoscale composites TiO2/ZnFe2O4powders were prepared by the polyacrylamide gel method. The effects of ZnFe2O4doping concentration and different sintered methods were studied on the properties and photocatalytic activities of TiO2. The results showed that the surface of TiO2was covered equably with dispersing highly nanocrystal ZnFe2O4, which accelerated the anatase-to-rutile phase transformation of TiO2and inhibited the growth of TiO2particles. The phase transformation temperature of TiO2was450℃sintered by muffle and400℃sintered by high temperature ball milling. The photocatalytic experimental results demonstrated that methylene blue could be photodegraded completely by TiO2/ZnFe2O4with2%wt ZnFe2O4doping concentration under visible light irradiation. The dope of ZnFe2O4has expanded spectrum response range of TiO2. The time for methylene blue being photodegraded to100%was only one third for the TiO2/ZnFe2O4powders sintered by high temperature ball milling than that by muffle. Accordingly, high temperature ball milling method can largely promote the refinement and decentralization of powders, then improve the photocatalysis.Secondly, the BaTiO3nanopowders were prepared by high temperature ball milling method under the condition of ball milling at700℃for3h, and ball to powder weight ratio up to30:1. The commonly used methods of preparation BaTiO3powders in industrial were calcining the barium titanyl oxalate BaTiO(C2O4)2(chemical method) or calcining the mixture powers of titanium dioxide TiO2and barium carbonate BaCO3(traditional solid state method). The production still had reactants barium carbonate and titanium dioxide, as well as intermediate material baryta after calcining the mixture powders of titanium dioxide and barium carbonate at1150℃. Both calcining the barium titanyl oxalate at900℃and ball milling at700℃can be applied to prepare BaTiO3nanopowders with a smaller average diameter about30nm, uniform particle size and good dispersivity. However, the preparation of precursor barium titanyl oxalate was economized by high temperature ball milling with lower calcination temperature. In our study, high temperature ball milling method was based on the original high energy ball milling by adding a controlled heating device. During ball milling, gradually increased the reaction temperature, this new method has promoted the rate of reaction and obtained high crystallinity products.Thirdly, luminescent lanthanide materials BaMoO4:Eu3+powders were prepared by chemical precipitation method using ammonium molybdate, barium nitrate and europium oxide as raw materials. Experimental results showed that a single phase of BaMoO4:Eu3+ can be obtained under the condition of8%Eu3+doping concentration, solution pH≈6, reaction temperature at80℃and sintering temperature at1000℃.The BaMoO4:Eu3+phosphors were synthesized by high temperature ball milling method using ammonium molybdate, barium carbonate and europium nitrate. Experimental results indicated that a single phase of BaMoO4:Eu3+can be obtained by ball milling with15%Eu3+doping concentrationat at600℃for4h and ball to powder weight ratio up to20:1.The even particle diameter size of irregular polyhedron shape BaMoO4:Eu3+was about3.96μm prepared by chemical precipitation method. The even particle diameter size of spheroid BaMo04:Eu3+was about1.06μm prepared by high temperature ball milling method with narrow size distribution, less aggregation and uniform dispersion, and so, it had stronger illumination performance. It was found that the powders can be excited efficiently by the ultraviolet light with wavelength394nm or visible blue light with wavelength465nm, and the highest luminous intensity was at616nm on the emission spectrum, where the luminescence was in reddish tone due to the dominant electric dipole transition from5Do to7F2.Fourthly, luminescent lanthanide materials SrMoO4:Eu3+powders were prepared by chemical precipitation method using ammonium molybdate, strontium nitrate and europium oxide as raw materials. Experimental results showed that a single phase of SrMoO4:Eu3+can be obtained under the condition of12%Eu3+doping concentration, solution pH≈7, reaction temperature at80℃and sintering temperature at800℃.The SrMoO4:Eu3+phosphors were synthesized by high temperature ball milling method using ammonium molybdate, strontium carbonate and europium nitrate. Experimental results indicated that a single phase of SrMoO4:Eu3+can be obtained by ball milling with20%Eu3+doping concentrationat at600℃for2h and ball to powder weight ratio up to20:1.The even particle diameter size of irregular polyhedron shape SrMoO4:Eu3+was about3.15μm prepared by chemical precipitation method. The even particle diameter size of spheroid SrMoO4:Eu3+was about0.86μm prepared by high temperature ball milling method with narrow size distribution, less aggregation and uniform dispersion, and so, it had stronger illumination performance. It was found that the powders can be excited efficiently by the ultraviolet light with wavelength394nm or visible blue light with wavelength465nm, and the highest luminous intensity was at616nm on the emission spectrum, where the luminescence was in reddish tone due to the dominant electric dipole transition from5Do to7F2.Fifthly, luminescent lanthanide materials CaMoO4:Eu3+powders were prepared by chemical precipitation method using ammonium molybdate, carium nitrate and europium oxide as raw materials. Experimental results showed that a single phase of CaMoO4:Eu3+can be obtained under the condition of25%Eu3+doping concentration, solution pH-7, reaction temperature at60℃and sintering temperature at900℃.The CaMoO4.Eu3+phosphors were synthesized by high temperature ball milling method using ammonium molybdate, carium carbonate and europium nitrate. Experimental results indicated that a single phase of CaMo04:Eu3+can be obtained by ball milling with33%Eu3+doping concentrationat at600℃for2h and ball to powder weight ratio up to15:1.The even particle diameter size of irregular polyhedron shape CaMoO4:Eu3+was about2.95μm prepared by chemical precipitation method. The even particle diameter size of spheroid CaMoO4:Eu3+was about0.71μm prepared by high temperature ball milling method with narrow size distribution, less aggregation and uniform dispersion, and so, it had stronger illumination performance. It was found that the powders can be excited efficiently by the ultraviolet light with wavelength394nm or visible blue light with wavelength465nm, and the highest luminous intensity was at616nm on the emission spectrum, where the luminescence was in reddish tone due to the dominant electric dipole transition from5Do to7F2.Sixthly, in the high temperature ball milling process, milling and temperature brought the energy acting on the reactants at the same time, then significantly increased the activation energy of the reaction system to promote the reaction quickly, which had realized the high temperature mechanochemistry. The synthesized temperature was decreased by about400℃,200℃and300℃while the Eu3+doped concentration was increased by about7%,8%and8%than those of chemical precipitation method for BaMoO4:Eu3+, SrMoO4:Eu3+and CaMoO4:Eu3+phosphor powders. High temperature ball milling has obtained the luminescent materials with strongest luminescence by easiest preparation technology, lowest reaction temperature, shortest reaction time and highest Eu3+doping concentration.Seventhly, the illumination performance of CaMoO4:Eu3+phosphor powders was stronger than BaMoO4:Eu3+and SrMoO4:Eu3+phosphor powders. While activator ion consists in crystal lattice, due to the effect of deformation force, its d electron cloud occurs deformation, then drills through valence band and is in metastable state. This procedure makes activator ion have illumination performance. The magnitude of deformation force is contingent on combined action of negative ion and positive ion in the crystal lattice of base material. In our three phosphor powders, Ba2+, Sr2+, Ca2+have been substituted by Eu3+. Owing to combined action of O2-and Mo6+, the comparison of ionic radius was R-Ba2+>Rsr2+>REu3+>Rca2+, but the illumination performance of them was the other way round, which demonstrated that the oppressive force was much larger than the derivational force of O2-and Mo6+on Eu3+electron cloud. |
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