Hong Bo Zhang

Preparation and Characterization of Na2O-Y2O3-P2O5-SiO2 Transparent Glass Ceramics

Transparent glass ceramics containing Na3.6Y1.8(PO4)3 crystals were successfully synthesized using high temperature melting quenching and subsequent heat treatment of the precursor glass with a composition 15Na2CO3-3Y2O3-45SiO2-31H3BO3- 5.4P2O5-0.6Sb2O3 (mol%). The impact of heat treatment is investigated in detail. The glass sample was tested by differential scanning calorimetry analysis to determine the heat treatment system. The ideal heat-treated condition is at 650°C for 2 h. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and scanning electron microscopy images, which indicate that Na3.6Y1.8(PO4)3 crystal were precipitated homogeneously among the glass matrix. The microstructural of precursor glass and glass ceramic were compared by analyzing FTIR spectra, indicating the formation of phosphate groups in glass ceramic. The refractive index of glass ceramics samples were measured. In the visible region, the transmittance of glass ceramics is up to 85%. Moreover, the relationship between the refractive index of the sample and the transmittance is discussed.

Preparation and Characterization of Tb3+/Eu3+ Co-Doped Na2O-Al2O3-SiO2 Glass Ceramics

Tb3+/Eu3+ co-doped sodium nepheline transparent glass ceramics with the weight percentage composition of 27Na2O-19Al2O3-23SiO2-13H3BO3-6TiO2-6ZrO2-3Tb4O7-3Eu2O3 were prepared by melting crystallization method. The heat treatment system, crystal phase, micromorphology, transmittance and luminescent properties of the samples were tested and characterized by DSC, XRD, SEM, UV-Vis-NIR and fluorescence spectrometer, respectively. The results show that the optimum heat treatment condition of glass at 480°C nucleated 1h and 580°C grew 1h., the crystal phase was NaAlSiO4(35-0424), and the incorporation of rare earth ions did not affect the crystal phase. The transmittance of glass ceramics in the visible area can reach 78%. The effect of different Tb3+/Eu3+ doping concentration on the luminescent properties of glass ceramic samples was discussed. It was found that there was a phenomenon of Tb3+ to Eu3+ energy transfer, and the luminescence effect was best when the percentage of mass of Tb3+/Eu3+ was 1:1.

Preparation and Optical Properties of Er 3+ -Yb 3+ Co-Doped ZnO-B 2 O 3 - SiO 2 -TiO 2 Transparent Glass-Ceramics

Er3+-Yb3+ co-doped ZnO-B2O3- SiO2-TiO2 transparent glass ceramics were synthesized by melt crystallization technique. Samples were characterized by DSC, XRD, SEM, UV-Vis-NIR and fluorescence spectra and the factors affecting the crystallization of glass ceramics were analyzed. The results indicated good crystallization property of ZBS glass ceramics. The optimum crystallization temperature was 800°C, and crystallization time was 60 min. The main crystal phase was Zn2TiO4 and the transmittance was up to 70% in visible light region. SEM micrograph indicated that the grain diameter was less than 100nm and the emission spectrum of glass ceramics displayed by fluorescence spectra was greatly improved compared with matrix glass. Strong emission peak was observed at 1535nm.

Research on Processing Conditions of CBS Transparent Glass-Ceramics

On the basis of experimental verification, the optimum processing conditions of CaO-B2O3-SiO2 (CBS) system transparent glass-ceramics were obtained. Composition of main raw powders (wt%) was:CaO 38%,SiO2 40%,B2O3 12%.The precursor glass was prepared by melting method and annealed at 560°C for 2h and cooled to room temperature at a speed of 5°C/min.The best nucleating agent is P2O5. The appropriate heat treatment regime to precursor glass was determined to be 2h at 600°C for nucleation and 3h at 780°C for crystallizition.Under this condition,the transmittion of glass-ceramics at the range of visable light is 72% in average and Sm3+ keep good luminescence property doped in this host material.

Synthesis of Nd:YAG Powders by the Co-Precipitation Method

Yttrium Aluminum Garnet (Nd:YAG) transparent ceramic doped with Nd have predominantly chemical stability, excellent optical quality and high temperature stability, it is becomeing a substitute for single crystal, had already become new generation laser material, have important strategic sense in the laser and the superelevation powders laser system. Al(NO3)3·9H2O, Y2O3, Nd2O3,(NH4)2SO4 and NH4HCO3 are raw material, TEOS is additive and ethylene glycol(EG). Nd:YAG precursor powders witch is Homogeneously dispersed, little agglomerated, pure YAG phase, different Nd3+ doped density were prepared by the co-precipitation method. The Nd:YAG ceramic powders were characterized by TG-DTA, XRD, FT-IR.

Synthesis and Characterization of the Sizing Agents on the Carbon Fibers

The recent development of carbon fiber sizing agent was introduced in this article. The sizing agent used in carbon fiber was synthesized at a temperature range of 55-60°C using epoxy resin and vinyl acetate as a monomer together, octyl phenol ethoxylated(OP-10) as the emulsion agent, ammonium peroxydisulfate as the solicitation agent and water as the dispersant. At the same time, the optimum composition, the optimum process condition and the effects affecting the emulsion stability were discussed. The characterizations were measured by Scanning Electron Microscopy and TG. The results show that the synthesis process is simple, low cost, less polution and remarkbably stable. The diameter of the particle is 1.8μm and the decomposition temperature is 260°C.

Preparation and Characterization of Sm3+ Doped CBS Transparent Glass-Ceramics

Sm3+ doped transparent glass-ceramics of CaO-B2O3-SiO2 (CBS) system were prepared and characterized.The precursor glass was prepared by melting method and annealed at 450°C for 2h and cooled to room temperature at a speed of 5°C/min.The appropriate heat treatment schedule to precursor glass was determined to be 2h at 600°C for nucleation and 3h at 810°C for crystallizition.The transmittion of glass-ceramics at the range of visable light is 68% in average. Five main emission bands of Sm3+ are centered around 564nm,605nm,646nm,679nm and 789nm,which correspond to the 4G 5/2→6H 5/2,4G 5/2→6H 7/2,4G 5/2→6H 9/2,4G 5/2→6H 11/2 and 4G 5/2→6H 13/2 transitions.Very strong luminescence at around 599nm is observed in glass-ceramics,This indicates glass-ceramics to be a better host for Sm3+ than precursor glass and a hopeful laser material.