What is glass corrosion?

Glass corrosion is the reaction of the content of glass with water or chemicals and the formation of residues in the form of stains on its surface.

Glass in architecture and construction has acquired a reputation of being one of the most durable building materials. However, based on the severity of exposure to contaminants through water, heat, and humidity, glasses experience staining or corrosion issues. Glass corrosion is the reaction of glass contents with water or chemicals and the formation of residues in the form of stains on its surface.

Improperly stored glass products may undergo glass corrosion, which would make them unsuitable for fabrication and installation. Understanding the circumstances under which the glasses are subjected to staining or corrosion can help glass handlers find the best way to prevent them.

This article discusses the significant causes and ways to prevent glass corrosion in the construction industry.

Causes of Glass Corrosion

Glass surfaces exposed to water or chemicals for an extended period of time result in severe chemical reactions. For example, the water present in the glass surface reacts with soda-lime-silica glass combinations. The interaction is subtle and slow, but the outcome appears either as corrosion or stains.

The phenomenon of glass corrosion is a combination of reactions. In Stage 1 reaction, a diffusion-controlled ion-exchange process occurs. Here, the sodium ion in the glass reacts with the hydrogen ions from water. In the process, the water leaches the sodium ion from the water. The reaction increases the pH of the glass surface due to the accumulation of hydroxide ions.

Higher the pH, the higher the alkalinity. The alkalinity of the contact surface also initiates more damaging reactions. Hence, the leaching observed on glass surfaces must be examined carefully.

The Stage 1 corrosion would last until the pH remains 9 in general conditions. During this period, the optical quality and the surface integrity of the glass remain unaffected.

Stage 2 reaction starts when the pH level reaches 9 or higher. During this level, the pH is enough to attack the glass silicate network. Microscopic pitting is observed in the initial stages of this reaction.

With the progression of the reaction, the surface damage occurs more. This stage affects the optical quality of the glass even if the integrity of the glass remains intact.

Atmospheric carbon dioxide can also react with the moisture in the glass surface, forming surface residues; sodium and calcium carbonates.

Prevention of Glass Corrosion

1. Corrosion in glass can be prevented if the surface is properly cleaned and dried. In addition, avoiding a corrosive environment helps to prevent damage to the glass surface.

2. Avoid improper cleaning procedures and chemical cleaners.

3. Use paper or powdered interleaving materials on glass surfaces to prevent abrasion and mechanical damage during shipping and handling. The interleaving system also neutralizes Stage 1 alkali buildup and pH control, thus preventing glass corrosion.

4. Consider choosing the appropriate type of glass based on the application.

5. For highly humid environments like bathrooms, employ anti-corrosive glass.