TEMPERATURE RANGES OF CORROSION RESISTANCE OF ENAMEL COATINGS.

The rate of reaction of acid and alkali solutions with enamel coatings depends to a large extent upon the temperature at which the equipment functions. With rise of temperature it increases, the increase being different at different levels. To determine the maximally admissible temperature of operation of enameled equipment having acid- and alkali-resistant UES-300 glass-enamel and Ts-4 glass-ceramic coatings, the authors studied their resistance to the corrosive action of mineral acid and alkali solutions of different concentrations c, determined the rate of corrosion of coatings under the action of the media at the testing temperature, and calculated the admissible operating temperature at several levels of the corrosion rate. The conditions of tests and the rate of corrosion of the coatings are given. It was found that when the enamel coatings are tested in accordance with ISO 27-43-75, ISO 27-45-73, and OST 26-01-1255-83, the rate of coating corrosion is much slower in 20% HCl and 4% NaOH than in boiling solutions.