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Molybdenum Electrodes Are Resistant to High Temperature During Glass Melting

Molybdenum metal is an indispensable material in glass melting applications. Its unique chemical properties, metal properties, mechanical and physical properties enable manufactures to produce high-quality molybdenum electrodes for glass melting. 

Globally, electrodes have been widely used in glass melting for many years, but the specific requirements for them used in glass melting and the understanding of its high-temperature processing technology have not yet been popularized. There are two producing processes - traditional powder metallurgy and the unique electron beam melting method (EB method). The purity ≥99.95%. 

Although moly electrode is extremely resistant to high temperature and high in strength, it is also extremely easy to be oxidized at high temperature.

During glass melting, the electrode starts to oxidize at 400°C, accelerates oxidation at 600°C, and oxidizes rapidly above 700°C and then produce MoO3. MoO3 is a volatile oxide that does not protect the electrode. Finally, the molybdenum will be corroded. Therefore, it exposed to the glass must be cooled to keep the temperature below 400°C, or to avoid contact with oxygen in the air.

When designing and using the electrode water jacket, it must be noted that at temperatures above 500°C, molybdenum will quickly be corroded in the air to generate easily volatile MoO3, so the electrode should be equipped with a cooling water jacket in the glass melting.

Fortunately, the electrode does not chemically react with the molten glass, and does not cause staining to the molten glass. A small amount of molybdenum is dissolved as an oxide in the glass melt, which will make the soda lime glass slightly yellow, but it is usually very slight. Therefore, it has no effect even on colorless glass. The molten glass with poor reducibility has much less corrosive effect on the molybdenum electrode than the molten glass with oxidizing properties.

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