Corrosion Behaviour of Bismuth-Silicate Glasses and their Glass-Ceramic Derivatives and the Effect of Ionizing Gamma-Irradiation

摘要

The corrosion weight losses by aqueous acidic or alkaline solutions have been studied for binary bismuth oxide-silica glasses and their corresponding glass-ceramic derivatives with the Bi_2O_3: SiO_2 molar per cent varying from 90:10 to 50: 50. The corrosive action on these glasses and glass-ceramics by acid solutions has been found to depend on the pH and the type of anion present in solution, and the attack by NaOH solution has been seen to be slightly lower than that by the acidic solutions. Generally, the corrosion decreases with the increase in the SiO_2 content in the samples as expected due to the strong structural role of silica in the glass network. Also, the corrosion has been found to increase with the microcrystalline compact glass-ceramic derivatives. Gamma-irradiation slightly changes the corrosion behaviour. Morphology of the glass surface changes has been studied by scanning electron microscopic (SEM) measurements. Various features of islands and surface cracks have been observed to be formed after subjecting the glass to the action of corroding solutions. In general, the bismuth silicate glasses and glass-ceramic derivatives are found to be of acceptable chemical durability and possess marked resistance to gamma-irradiation.