Yasuhiko¡¡GANAHA
Reaction Mechanism of Phosphate Glasses in Hydrofluoric Acid
Kazumasa MATUSITA
It is well known that glasses are dissolved in hydrofluoric aicd remarkably. However, there have been few reports on dissolution rate of glasses in hydrofluoric acid.
Then in the present study, relationship between composition of the glasses and rate of dissolution was revealled in order to understand dissolution mechanism and to develope glasses which have high resistanse to hydrofluoric acid.
The glass was soaked in hydrofluoric solutions, and weight decrease of glass was measured. Dissolution rate was calculated from weight decrease.
As a result, it was found that some phosphate glasses have extraordinaliry high resistance to hydrofluoric acid. These phosphate glasses have dissolution rate in hydrofluoric solutions 1/5000 or less than silica glass, which have the highest resistance among silicate glasses. Also, transparent glasses were developed which have very high resistance to hydrofluoric acid.
In addition, dissolution rates in various acid and base solutions for example NaOH and HCl solution were measured in order to estimate resistance to acid and base
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