Glass melting electrodes are a used industrial plants, where, as the name suggests, they are used melt glass. This typically happens in a glass manufacturing plant, among other place, and glass melting electrodes must be able to stand up to enormously high temperatures and electrical currents.
How Are Glass Melting Electrodes Made?
Since furnace electrodes must be able to handle high temperatures and currents, a glass melting electrode will typically be made from molybdenum. This material was only recognized as an official element and added to the table of elements late in the eighteenth century, but since that time it has been used extensively in many applications.
Molybdenum has one of the highest melting points of any element on Earth at approximately 4,748 degrees Fahrenheit. Only tungsten is higher at 6,170 degrees. It is also relatively easy to machine and has very low thermal expansion but high electrical conductivity.
Because of the pressures the glass melting electrodes will be under, molybdenum manufacturers must make molybdenum glass melting electrodes to purity levels of over 99%. This ensures the electrodes will be able to withstand heat and chemical corrosion. It also minimizes any discoloration of glass during the melting process.
Are Molybdenum Electrodes Mixed With Anything?
While it is important to have high molybdenum purity levels, most molybdenum manufacturing methods for producing glass melting electrodes will also include a small amount of zirconium oxide. This helps to increase efficiency in the finished product and offers slightly greater resistance to corrosion from melting glass by products than pure molybdenum.
How Do Glass Melting Electrodes Work?
Glass was likely first discovered when cooking fires accidentally created them. These early bits of glass seem to have been used by people as decorations, but soon glassmaking became intentional. Limits on glassmaking were due entirely to the heat limits of furnaces powered coal or wood.
With the discovery of electricity, people gained the power to make furnaces that far more powerful. In the 1950s, scientists discovered how to apply this to glassmaking, and the use of molybdenum in electrodes become common.
The electrodes work by passing an electrical current directly through a molten glass bath. The molybdenum itself boosts the electrical power and directs it at the glass. The glass in turn protects the molybdenum from rapid oxidation by protecting it from the air, and this symbiotic relationship ensures that the electrodes can be used over and over again.
The glass we see and use around us everywhere in the modern world is largely made in a vacuum furnace using molybdenum glass melting electrodes. These pieces of glass are in our smartphones and computers, in the windows of high rise office buildings, in high-speed internet cables and in television displays. It is safe to say that modern life would not be possible with the glass melting electrode.