Qiu Guanming

Application of Rare Earths in Advanced Ceramic Materials

Abstract The electronic structure of rare earth elements, the analysis of spectral characteristics and chemical properties were outlined. The application of rare earth elements in ceramic oxides, non-oxide ceramic materials, as well as functional ceramic were described.

Synthesis of Long Afterglow Phosphors Doped B SrAl2O4:Eu2+, Dy3+ and Its Luminescent Properties

Abstract The long afterglow luminescent material SrAl 2 O 4 : Eu 2+ , Dy 3+ was prepared by high temperature solid-state method. Effects of doped B on the luminescent properties of phosphors SrAl 2 O 4 : Eu 2+ , Dy 3+ were investigated by means of excitation spectra, emission spectra and X-ray diffraction analysis. As the result, the addition of H 3 BO 3 as flux promotes the growth of crystalline and reduces the synthesizing temperature, but the wavelength of emission peak of photoluminescent material did not change with the variation of H 3 BO 3 content. The effect of Dy 3+ concentration on the luminescent properties of material was investigated. It was found that the luminescence of phosphors prepared under the condition of the amount of H 3 BO 3 5% and the mole ratio of Eu/Dy = 1/7(Eu = 0.02 mole) had better luminescent property and longer afterglow time.

Study on Properties and Synthesis of Fluorescence PMMA

Abstract Ammonium acrylate-1,10-phenanthroline rare earth complexes were synthesized by using rare earth oxides. The rare earth complexes were co-polymerized with methyl-methacrylate (MMA) by radical copolymerization. The rare earth polymer photo luminescent material was obtained. The thermodynamics properties of the copolymer were analyzed by STA. Infrared detector was used to demonstrate the structure of the polymer. XRD was used to analyze the influence on the crystal property of the co-polymer. The fluorescence intensity of the co-polymer was analyzed by fluorescence spectrum. The different influence on the emission intensity from the co-polymer of different formula was studied. The result showed that emission intensity of the co-polymer was changed when different concentration of the rare earth ion in synthesizing the compounds. The concentration quenching appeared when the concentration of rare earth complexes arrived at some value.

Synthesis and Characterization of Rare Earth Complexes

Abstract Rare earth (Eu 3+ ) single nuclear chelated with α-methacrylic acid and 1, 10-phenanthroline, as well as the heteronuclear chelated of Eu 3+ and La 3+ ions, were synthesized. The composition and structure of the rare earth complexes were confirmed by IR, SEM and XRD. The thermal analysis indicated that the heat-stability was improved. Moreover, the fluorescence spectra proved that the complexes had good fluorescence property. The results showed that it was convenient to synthesize series of europium chelate. The complexes exhibited characteristic fluorescence of europium. ion. The sensitization of La 3+ could enhance the fluorescence emission intensity of Eu 3+ ion.

Al2O3/TiCN-0.2% Y2O3 Composite Prepared by HP and Its Cutting Performance

Abstract Al2O3/TiCN-0.2% Y2O3 composites were fabricated by hot pressing sintering. The effect on mechanical property and microstructure of the sample composition and HP temperate was investigated. The results of Al2O3/TiCN-0.2% Y2O3 were satisfied. The bending strength, fracture toughness, Vickers hardness was respectively 1015 MPa, 6.89 MPa·m1/2 20.82 MPa at 1650 °C for 20 min. Good wear resistance was found for the kind of ceramic material when used as cutting tools in the machining of the hardened carbon steel. By the compared experiment for the cutting performances, it could be seen that the performance of this composite material was better than that of the ceramic tool material YT15 for continuously cutting quenched steel. This kind of composite tool material is suitable for continuously cutting quenched steel No.45, especially intermittently cutting quenched steel.

Synthesis of Al2O3/TiCN-0.2%Y2O3 Composite by Hot Pressing

Abstract Al2O3/TiCN composites were synthesized by hot pressing. The influences of components and HP temperature on mechanical properties, such as bending strength, breaking tenacity and Vickers hardness were investigated. The results showed that the mechanical properties of Al2O3/TiCN composite increased with temperature when hot pressing temperature is below 1650 °C. The mechanical properties reached their maximums when the composites were sintered at 1650 °C for 30 min under hot pressing pressure of 35 MPa, the value of bending strength, breaking tenacity and Vickers hardness was 1015 MPa, 6.89 MPa · m1/2, and 20.82 MPa, respectively. When hot pressing temperature was above 1650 °C, density decreased because of decomposition with increased temperature, and mechanical properties dropped because of rapid growth of grains in size at high temperature. Microstructure analysis showed that the addition of Y2O3 led to the formation of YAG phase so as to inhibit the growth of crystals. This helped to improve breaking tenacity of the composites. TiCN particles with diameters of 1 μm dispersed at Al2O3 grain boundaries, inhibited grain growth and enhanced mechanical properties of the composites. SEM study of the propagation of indentation cracks showed that the bridge linking behavior between matrix and strengthening phase might lead to the formation of the coexisted field of crack deflection, branching and bridge linking. The mechanism of this phenomenon was that the addition of Y2O3 improved the dispersion of TiCN particles so as to enhance the tenacity of the composites. The breaking tenacity was changed from 5.94 to 6.89 MPa · m1/2.

Study on Red Long-Time Luminescent Material Y2O2S:Eu, M (M = Mg, Ca, Sr, Ba)

Abstract The red long-time luminescent material Y2O2S:Eu3+, M (M = Mg, Ca, Sr, Ba) was prepared by high temperature solid-state method. The XRD result of the sample showed that the crystal phase was Y2O2S, which belong to hexagonal system, and no new crystal phase were by doping different amount of Mg, Ca, Sr, Ba. The excitation spectrum was a broad band within 200 × 400 nm region, the characteristic peaks of emission spectrum were located at 583, 595, 597, 617, 627, 707 nm. There was no marked change in excitation spectra, emission spectra and maximum of their wavelengths of the luminescent materials by doping with different ions. The luminescent intensity of the phosphors were stronger when the concentration of doping ions was Mg/Y = 6%, Ca/Y = 4%, Sr/Y = 8%, Ba/Y = 2.5%, respectively. Its sequence of luminescent intensity from high to low is Sr > Ba > Mg > Ca.

Preparation of Orange-Red Long Afterglow Phosphors Y2O2S:Sm3+, Mg2+, Ti4+

Abstract The orange-red long afterglow phosphors Y2O2S:Sm3+, Mg2+, Ti4+ was prepared by high temperature solid-state method. By XRD analysis, the crystal phase of the sample was Y2O2S, belonging to hexagonal system, and no new crystal phase arose when doping Sm3+, Mg2+, Ti4+. The characteristic peaks of excitation spectrum were located at 373, 388, 417, 430, 475 and 491 nm, and the characteristic peaks of emission spectrum were located at 571, 609 and 657 nm. The content of Sm3+ and doped ions Mg2+, Ti4+ affected the luminescent properties obviously, and Sm3+ affected the luminescent brightness mainly. Mg2+ and Ti4+ could deepen properly trap energy of Y2O2S crystal and strengthen its afterglow properties, the brightness and afterglow properties of sample were better when the mole ratio of Sm/Y, Mg/Y and Ti/Y is 1.4%, 1.25% and 0.9%, respectively.

Research on Electrorheological Fluid Containing Rare Earth Cerium

Abstract Electrorheological fluid was prepared by inducting rare earth cerium into mixture of nano-silicon dioxide/hydroxyl silicon oil and its structure was analyzed by infrared spectra. The results showed that rare earth modified SiO 2 , obtained by reaction of acrylic acid cerium and silane coupler, had big electrorheological effect which hydroxyl silicon oil acted as dispersed medium. The electrorheological fluid had high stability and showed change of solid-fluid at low electric field (1 kV·mm −1 ). Diluted experimentation by using methylic silicon oil showed that rare earth cerium could not only enhance polarization of SiO 2 but also the interaction of SiO 2 and hydroxyl silicon oil and hydroxyl silicon oil could boost electrorheological effect by polarizing in electric field.

Modification Research on Polypropylene with Acrylic-Silicon Oil Lanthanum

Abstract It is hard that inducting rare earth into common resin by bond combination. General plastic polypropylene (PP) containing rare earth was prepared by the bond combination of PP and acrylic-silicon oil lanthanum, which was obtained by reaction of acrylic acid ethylene silicon oil. The principle and method of the graft copolymerization of PP and acrylicsilicon oil lanthanum were discussed. The graft copolymer was characterized by scanning electron microscope (SEM). The mechanical property of graft copolymer was measured by electronic tensile testing machine and impact testing machine. The experimental results showed that crosslinking reaction between PP and acrylic-silicon oil lanthanum happened, acrylic-silicon oil lanthanum did not harm PPs performances. PPs tensile strength almost kept the same and impact strength obviously increased.