Causes and treatment of mildew in glass
[China Glass Net] Causes and treatment of glass mold
I. Overview
In the process of preparing glass products by the traditional melting method, in order to reduce the cost, soda ash is selected as the flux, which is accompanied by the easy weathering of the glass products under certain conditions (commonly known as mold).
Moldy glass is a problem that occurs during storage and transportation. After the mold, the surface of the glass product will lose its luster, lose its transparency, and appear rainbow, white spots or patches (not easy to separate).
Glass mold usually occurs on the air surface (top) of the float glass. This is because the lower surface of the float glass is in contact with the tin liquid, and a thin layer of tin is infiltrated into the surface to protect the glass.
Second, the mold of glass can be divided into the following stages:
1. Water or moisture is adsorbed on the glass surface.
2. Subsequently, water or moisture diffuses into the glass.
3. The soluble silicate in the surface layer is hydrolyzed and destroyed. First, sodium silicate and potassium silicate are hydrolyzed and destroyed. Caustic soda (NaOH) is formed and SiO2 is separated.
4. The separated SiO2 forms a silicone gel which forms a protective film on the surface of the glass which prevents further erosion.
5. The caustic soda formed by hydrolysis reacts with carbon dioxide in the air to form sodium carbonate, which accumulates on the surface of the glass to form a soluble salt in the surface film. Due to its strong hygroscopicity, it absorbs moisture and deliquesces, forming lye droplets. As the surrounding temperature and humidity change, the concentration of these droplets also changes. If the concentrated lye droplets are in contact with the glass for a long period of time, the gel-like silicone film can be partially dissolved therein, causing severe local erosion of the glass surface to form spots. This is a group of white alkali-rich ions that are formed by the migration of sodium ions from the glass body and reacting with air. A white particle swarm can be observed by scanning electron microscopy.
Third, the glass mold is related to what factors
Fourth, moldy identification and inspection methods
The visual appearance method is a simple and feasible method. The specimen was placed in reflected light and transmitted light to observe the presence or absence of spots and mist on the surface of the glass under concentrated light. These spots and mists cannot be wiped off with cloth or water. The glass in which the above phenomenon occurs indicates that the sample has been moldy. If concentrated glare is observed, a small number of spots and mists are slightly mildewed by the naked eye. If concentrated glare is observed, many spots and light mists are observed by the naked eye. If there is no concentrated beam of light, some spots and fog are observed by the naked eye to be severely moldy.
Moldy can also be observed by spray wetting under natural light.
Custom Metal Keychains,Coin Keychain,Keychain Metal
Shenzhen MingFengXing Art & Craft Products CO., LTD. , https://www.mf-gift.com