| Corrosion |
CORROSIONThe rate of corrosion of TYCON technoglass coatings depends on different factors such as:
TYPES OF CORROSIVE SUBSTANCESBy their very nature, TYCON technoglass coatings are resistant to all the organic or inorganic acids, oxidising or reducing, with the sole exception of hydrofluoric acid that, even as a mere impurity, is capable of corroding them by an attack on the siliceous structure. Basic substances are more corrosive than acid. Due to the considerable improvements achieved over recent years, TYCON technoglass coatings can now also be used in a vast range of basic processes. An attack on these coatings by solvents and organic substances in general is negligible even at very high temperatures, irrespective of the presence of halogens in the molecules. TYCON technoglass coatings and linings are also highly resistant to gases, not condensing steam, molten acid or neutral salts up to temperatures approaching the limit of physical utilisation. PRODUCT LIST AND RESISTANCE OF THE GLASS-LININGS 808, 809 AND 805The resistance of the glass-linings 808, 809 and 805 as compared with a number of the most common chemical substances is shown in our brochure. It should be noted that the temperatures and the data listed do not constitute in any case neither the maximum limit, nor a guarantee for use the glass-lining. Since their value is purely in quality it is advisable to consult us for each special problem. TEMPERATUREThe effect of temperature on corrosion is very evident for both acids and bases. Generally, for bases, it can be assumed that the rate of corrosion is doubled for every 10 °C increase in temperature. The isocorrosion curves, (which represent the loss of the lass-lining thickness in mm/year) and the data given later, refer to 808, ..9 ..5 glasses and have been obtained by laboratory experiment with tantalum autoclaves having a volume/surface ratio of 73. A corrosion rate of 0.15 mm/year corresponds to the maximum limit that we suggest for continuous service. A corrosion rate of 0.25 mm/year corresponds to the maximum limit that we suggest for intermittent service. A corrosion rate of 0.5 mm/year corresponds to the maximum limit that we suggest for operation in particularly corrosive conditions carried out only in exceptional circumstances. The curves refer to tests carried out with pure products. The presence in mixes of other substances that can act as accelerators or inhibitors may cause the rate of corrosion to change even considerably. Since it is impossible for us to foresee or control the conditions in which our vessels may be used, it is advisable to consult us directly for each particular application.
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