Glass in water

The mechanism of subcritical crack growth is the reaction of the corrosive medium with highly stressed bonds at the crack tip. In siUca, in the absence of stressed bonds, the rate of the reaction between the bonds and corrosive media such as water is very low. The introduction of strain energy into crack tip bonds increases the activity of the bond. For siUca glass in water, attack and bond breakage occurs by the following reaction (47) ... 

The attack of most glasses in water and acid is diffusion controlled and the thickness of the porous layer formed on the glass surface consequently depends on the square root of the time. There is ample evidence that the diffusion of alkali ions and basic oxides is thermally activated, suggesting that diffusion occurs either through small pores or through a compact body. The reacted zone is porous and can be further modified by attack and dissolution, if alkali is still present, or by further polymerisation. Consolidation of the structure generally requires thermal treatment. 

Atomization" of liquids and solids Rate of "atomization" of mercury and glass in water accelerated... 

Perera, G., Doremus, R.H. and Lanford, W. (1991). Dissolution rates of silicate glasses in water at pH 7. Journal of the American Ceramic Society 74 1269-1274. 

Crovisier, J. L., Vernaz, E., Dussossoy, J. L. Caurel, J. 1992b. Early phyllosilicates formed by alteration of R7T7 glass in water at 250°C. Applied Clay Science, 7, 47-57. 

Release rate data for radionuclides from fully radioactive waste forms are needed to evaluate the safety of nuclear waste glass. Presently, contact with water is considered the most important release path therefore, the release properties of waste glass in water are of primary concern. 

Figures 4 and 5 summarize the zeta potentials that were measured on pure silica, 0% B20, glass, and 6% B,0, glass—in water and silane solutions. The zeta...

A 10-12% solution of ethanol collected. In the hood place three drops of distillate on a Pyrex watch glass in water is produced by fer- and try to ignite it with the blue cone of a microburner flame. Does it burn mentation. See Chapter 18. Is any unburned residue observed ... 

In the case of S-glass in water, magnesium in the form of hydroxide is the most soluble compared to Si02 and AI2O3 (9). 

For data on the solubility of glass in water and other solvents, see ... 

Explain the process of dissolution of a sodium trisilicate glass in water. Explain the effect of pH on the process. Explain why a sodium alumino-silicate glass is more durable than a sodium silicate glass in water, but is less durable in a strong acid. 

However, Kondo [3 ] is of the opinion that the hydrolysis of the glass in water occurs and the calcium ions are released initially to the liquid phase. Simultaneously on the surface of slag grains an acid, colloidal shell of silica-alumina gel is formed. This shell has low permeability and hence the further slag reaction with water is hindered. In the presence of Ca(OH)2, added as alkaline activator, the siUcon and aluminum from the shell are released to the solution (Fig. 8.2). The solubiUty of aluminum compounds becomes considerably increased in the solution of pH higher than 12.5 because in this condition the Al(OH) ions are formed [4]. The concentration of aluminum in the liquid phase is increasing because the calcium aluminates crystallize a httle later, primarily the C-S-H (1) is formed. Simultaneously the solubility of hydrates formed in this condition is reduced. 

Perera, G., R.H. Doremus, and W. Lanford, Dissolution Rates of Silicate Glasses in Water at pH 7. Journal of the American Ceramic Society, 1991. 74(6) p. 1269-1274. Andersson, P., A.-P. NikkilS, and P. Lintula, Wear chartutieristics of water-lubricated SiC journal bearings in intermittent motion. Wear, 1994.179 p. 57-62. 

Fig. 7.8. Dependence of the crack-growth rate on the stress intensity factor of soda-lime glass in water and toluene (phenylmethane) at 25°C [104]...

Values of for soda-lime glass in water and air environments gave average n values of 15.7 and 23.3, respectively, which are typical of values found by less convenient methods. 

Remarkably few isolable complexes exhibit silver-silver covalency. The ionization potential [144] and bond length (2.5310(10) A) [145] of singly bonded Ag-Ag have been determined by spectroscopic studies on supersonic beams. Small clusters Ag ( = 2-5) have been synthesized and studied in an argon matrix [146], and the gas-phase synthesis and reaction chemistry of mixed-valent silver(0/I) clusters have been studied by mass spectrometry [147]. Pulse radiolysis of Ag+ solutions or glasses in water and ethanol has allowed the study of unstable clusters as intermediates in metal colloid formation thus, the absorption and EPR spectra of [Ag2], [Ag4], and [Ag4] have been recorded [148]. These are fully delocalized Ag(0,I) ions in which partial occupation of silver 5s-orbital combinations leads to net metal-metal bonding. 

Figure 3 shows scratch hardness of soda-lime glass in water and in n-alcohols. Scratch hardness increases with an increase in the number of carbon atoms in each alcohol molecule, but shows a maximum at 1-decanol. Scratch hardness obtained in 1-decanol is 28% larger than that in 1-pentanol. Scratch hardness obtained in water is comparable with that in 1-pentanol. 

The crack initiation test was performed for silica, Tempax, and soda-lime glasses in water and in dehydrated heptane by using the scratch tester. Figure 5 shows an... 

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