Insight into silicate-glass corrosion mechanisms

Area of Science:

• Materials Science
• Geochemistry
• Physical Chemistry

Background:

• Silicate glass exhibits excellent chemical durability, crucial for various applications.
• Aqueous glass corrosion kinetics typically slow down over time, often attributed to solution saturation with silica.

Purpose of the Study:

• To investigate a novel mechanism behind the slowdown of glass corrosion kinetics.
• To elucidate the role of morphological transformations in the alteration layer on leaching behavior.

Main Methods:

• Coupling structure-sensitive experimental results with mesoscopic-scale numerical simulations.
• Investigating the correlation between the structure and reactivity of the glass alteration layer.

Main Results:

• A new mechanism for the slowdown of glass corrosion is identified.
• The sharp decrease in corrosion rate is linked to the densification and pore closure of the outer alteration film.
• Insoluble elements within the glass were found to inhibit the restructuring of the alteration film.

Conclusions:

• The observed slowdown in glass corrosion is primarily due to physical changes (densification, pore closure) in the alteration layer, not solely chemical saturation.
• This mechanism of pore closure and its inhibition by insoluble elements may extend to silicate minerals.