Effect of TiO 2 on microphase development during phase separation and crystallization in Na 2 O‐B 2 O 3 ‐SiO 2 glass system

In the B2O3–Al2O3–SiO2–P2O5 glass system, the structural heterogeneity leads to nano-phase separation and structural ordering upon cooling and heating, respectively.

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Effects of Heat Treatment Temperature on the Photocatalytic Properties of TiO2 Prepared by Melt-Phase Separation Process

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1989 ◽

2007 ◽

Vol 336-338 ◽

pp. 1989-1991

Author(s):

Wen Li Zhang ◽

Yin Lin Wu ◽

Ying Na Zhao ◽

Xiao Li Zhang ◽

Hao Man Li

Keyword(s):

Heat Treatment ◽

Phase Separation ◽

Heat Treatment Temperature ◽

Glass Phase ◽

Heat Treatment Condition ◽

Treatment Temperature ◽

Separation Process ◽

Glass System ◽

Phase Separation Process ◽

Melt Phase

The principle of melt-phase separation process for preparation of nanoparticle TiO2 is based on the adjustment of glass phase-separation structure. TiO2 grain size can be controlled by changing heat treatment temperature. The sample was composed of Na2O-B2O3-SiO2-TiO2 glass system (melted at 1573K). A photocatalytic nanoparticle TiO2 which was loaded on porous glass can be obtained by heat treatment of glass system at various temperatures and then acid washing. The results have shown that the glass phase-separation structure size matches crystallization rate and an optimal photodegradation property of TiO2 is achieved. It was found that the suitable heat treatment condition was at 848K for 12h, although its performance slightly changes with the composition variations.

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Bulk standards for low-temperature biological x-ray microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111525 ◽

1984 ◽

Vol 42 ◽

pp. 282-283

Author(s):

P. Echlin ◽

M. McKoon ◽

E.S. Taylor ◽

C.E. Thomas ◽

K.L. Maloney ◽

...

Keyword(s):

Phase Separation ◽

Low Temperature ◽

Analytical Method ◽

Salt Solutions ◽

Absolute Concentration ◽

Cooling Process ◽

X Ray ◽

The Absolute ◽

Analytical Procedures ◽

Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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Phase separation in sol gel-derived ceramic films of silica-zirconia, alumina-zirconia, and titania-zirconia system

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170967 ◽

1994 ◽

Vol 52 ◽

pp. 646-647

Author(s):

J. Tong ◽

L. Eyring

Keyword(s):

Fracture Toughness ◽

Phase Separation ◽

Sol Gel ◽

Great Influence ◽

High Strength ◽

Chemical Durability ◽

Separation Method ◽

Toughening Mechanism ◽

Ceramic Films ◽

Zirconia Toughened Alumina

There is increasing interest in composites containing zirconia because of their high strength, fracture toughness, and its great influence on the chemical durability in glass. For the zirconia-silica system, monolithic glasses, fibers and coatings have been obtained. There is currently a great interest in designing zirconia-toughened alumina including exploration of the processing methods and the toughening mechanism.The possibility of forming nanocrystal composites by a phase separation method has been investigated in three systems: zirconia-alumina, zirconia-silica and zirconia-titania using HREM. The morphological observations initially suggest that the formation of nanocrystal composites by a phase separation method is possible in the zirconia-alumina and zirconia-silica systems, but impossible in the zirconia-titania system. The separation-produced grain size in silica-zirconia system is around 5 nm and is more uniform than that in the alumina-zirconia system in which the sizes of the small polyhedron grains are around 10 nm. In the titania-zirconia system, there is no obvious separation as was observed in die alumina-zirconia and silica-zirconia system.

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