Silica glass,

Five shock experiments for SiCh glass were performed at pressures of 17.8, 21.8, 26.3, 32.0, and 43.4 GPa. The measured refractive index, n, and density, p, are shown in Fig. 3.9. X-ray diffraction data were measured with Mo-Ka radiation. Raman spectra in the range 115-1200 and 400-1400 cm-1 were measured for each sample [26,32,70]. 

The corrected Raman spectra of normal and shock-densified Si02 glasses are shown in Fig. 3.11. The Raman bands show significant pressure variations in frequency, bandwidth, and relative intensity (Fig. 3.12). The broad band near 455 cm-1 shows large variations of frequency and width. Generally, there is an inverse correlation between the frequency of this band and the Si-O-Si angle 

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There are two classes of solids that are not crystalline, that is, p(r) is not periodic. The more familiar one is a glass, for which there are again two models, which may be called the random network and tlie random packing of hard spheres. An example of the first is silica glass or fiised quartz. It consists of tetrahedral SiO groups that are linked at their vertices by Si-O-Si bonds, but, unlike the various crystalline phases of Si02, there is no systematic relation between... 

Figure Bl.20.8. DLVO-type forces measured between two silica glass surfaces in aqueous solutions of NaCl at various concentrations. The inset shows the same data in the short-range regime up to D = 10 mn. The repulsive deviation at short range (<2 nm) is due to a monotonic solvation force, which seems not to depend on the salt concentration. Oscillatory surface forces are not observed. With pemiission from [73].

When silica is fused,. silica glass is formed. This has advantages over ordinary glass in that it is much less easily fused (it softens at about 1800 K). and has a very low coefficient of expansion. It is. therefore, used for crucibles and other articles required to be infusible... 

Platinum is a beautiful silvery-white metal, when pure, and is malleable and ductile. It has a coefficient of expansion almost equal to that of soda-lime-silica glass, and is therefore used to make sealed electrodes in glass systems. The metal does not oxidize in air at any temperature, but is corroded by halogens, cyanides, sulfur, and caustic alkalis. 

Sodamide Soda-silica glass Soda-sinter process Sodatol... 

Vitreous silica (silica glass) is essentially a supercooled Hquid formed by fusion and subsequent cooling of crystalline silica. It is found ia nature ia fulgerites, ie, fused bodies resulting from lightning striking quart2 sand. 

I. FanderHk, ed.. Silica Glass and its Application Elsevier Science PubHshers, New York, 1991, pp. 165—166. 

Typical applications include careful sizing of silica-glass sand, washing phosphate rock, sizing of abrasives, smokeless powder, sodium ahi-rninate, etc,... 

Cobalt/tungsten carbide cermets 400-530 Silica glass, Si02 (quartz) 94... 

Silica glass transmits 92% of the radiation in the wavelength region of 0.3-2.7 pm, and it is impervious to other radiation. Determine the wavelength of the sun s radiation that the glass transmits when the sun is treated as a blackbody, T = 5600 K, What happens for a blackbody at a temperature of 295 K. ... 

Finally in this section we mention iodine oxide pentafluoride, F5IO, obtained as a colourless liquid, mp 45°, when IF7 is allowed to react with water, silica, glass or I2O5. As implied... 

Electronic materials are needed for computers and control devices purified silicon is the basic material for these applications. In addition silica glass (SiOj) is ail insulator, ahiininum an electrical conductor, and polymers are reactive materials for patterning in these devices. Control of evei"y step of energy production and traiismission is now completely dependent on electronics. 

Gulaev, V. M. The Strength and Deformation Properties of Vitreous Silica , Glass Ceramics, 30 No. 6, 279 (1973)... 

The purity of 1 and 2 is assessed by analytical gas-liquid chromatography (GC) on a Hewlett-Packard 5890 gas chromatograph equipped with a flame-ionization detector and fitted with a 50 m x 0.2 mm HP-5 fused silica glass capillary column using linear temperature programming from an initial temperature of 150°C for 5 min to a final temperature of 200°C for 10 min at a rate of 5°C/min. 

The main problem in developing fibers for IR transmission is that silica glass is not transparent in that area of the spectrum. Suitable materials include the selenides and other chalcogenide glasses (particularly for the CO2 laser light source) and the fluorohafnate glasses. In addition, materials, such as zirconium fluo-... 

There are, however, differences which are best illustrated by reference to the simple example of silica glass and silica gel. In silica glass, Si is four-coordinate and the polymeric links are of the bridging type ... 

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