Kinetics glass corrosion

Sanders, D.M., Person, W.B. and Hench, L.L. (1972). New methods for studying glass corrosion kinetics. Applied Spectroscopy 26 530-536. 

Towards a consistent rate law glass corrosion kinetics near saturation... 

There are a number of mechanisms that pose potential problems to predicting dissolution rate kinetics as the system approaches saturation. Part of this conundrum originates from current models of glass corrosion kinetics that cannot yet incorporate these unanticipated phenomena into a mathematical equation that is consistent with the constraints of thermodynamics or kinetics. These phenomena include (1) alkali-hydrogen exchange (2) dissimilar reactivity of... 

Kinetics of Ceramic and Glass Corrosion by Gases. The attack of ceramics and glasses by gaseous reactants is much more prevalent than corrosion due to liquids. In addition to the chemical composition of the attacking medium, the geometry of the ceramic solid is of tantamount importance to its corrosion resistance. That is, a... 

The previous sections dealt primarily with phase transformations and corrosion in materials. Polymers also undergo phase transformations. For example, there are many polymers that utilize nucleation and growth kinetics to transform from amorphous to crystalline polymers. The kinetics of these transformations are very similar, in principle, to the preceding descriptions for glasses, so it is not necessary to duplicate that material here. Polymers also are susceptible to corrosion, but the term degradation is more... 

The applications of TGA are extensive and diverse and include oxy-salt decompositions, natural and synthetic polymer characterization, metal oxidation and corrosion analysis, compositional analysis of coals, polymers, and rubbers, study of glass materials, foodstuffs, catalytic materials, biological materials, and a wide range of chemical processing phenomena. It has been used very successfully to study the kinetics of chemical processes however, there is much controversy surrounding this application, particularly in terms of relating TGA data to reaction kinetics models. 

Polymer chemists use DSC extensively to study percent crystallinity, crystallization rate, polymerization reaction kinetics, polymer degradation, and the effect of composition on the glass transition temperature, heat capacity determinations, and characterization of polymer blends. Materials scientists, physical chemists, and analytical chemists use DSC to study corrosion, oxidation, reduction, phase changes, catalysts, surface reactions, chemical adsorption and desorption (chemisorption), physical adsorption and desorption (physisorp-tion), fundamental physical properties such as enthalpy, boiling point, and equdibrium vapor pressure. DSC instruments permit the purge gas to be changed automatically, so sample interactions with reactive gas atmospheres can be studied. 

To this point, it has been assumed that failure occurs when K =T (or G=R) but, in studies of fracture, it is sometimes found that crack growth can occur at lower values of or G. Thus, kinetic effects must be included in any general formalism. There are several mechanisms that can give rise to sub-critical crack growth, but most attention has been directed to stress corrosion. This behavior has been extensively studied in silicate glasses but it can also occur in many polycrystalline ceramics. Figure 8.72 shows a typical response of ceramics to stress corrosion, with crack velocity v plotted as a function of K (or G). At low values of K, there often appears to be a threshold value of the stress intensity factor below which... 

FIGURE 13 Examples of kinetic processes classified by types of phases involved, (a) Gas-gas reaction equilibrium between hydrogen gas, iodine gas, and hydrogen iodide gas. (f>) Gas-Uquid evaporation of liquid water from a glass, (c) Liquid-Liquid gradual separation of an oil-water mixture, (d) Gas-solid chemical vapor deposition of a thin Si film, (e) Liquid-solid corrosion of Cu metal in seawater, (f) Solid-solid precipitation of CuAlj particles from a copper-aluminum alloy during a heat treatment process. 

R. J. Charles and W. B. Hillig, The kinetics of glass failure by stress corrosion, in Symposium sur la resistance mecanique du verre et les moyens del ameliorer, Florence (Charleroi Union Scientffique Continentale du Verre, 1962), pp. 511 527. 

Solid glass and glass fibers are attacked by acids, alkalis, and also by water. Here, the attack mechanisms of acids and alkalis are fundamentally different. While glass fiber corrosion by acids is diffusion-controlled following 7f-kinetics, attack by water and alkali is more linear and controlled by interfacial properties. 

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