Glass is one of the most ancient and universal materials. Glass products surround us everywhere, but usually we don’t think too much about its characteristics. They can vary greatly depending on the purpose of use of the future product. One of the most common types is heat resistant glass. Let's find out how it differs from the usual one and where it is applied.
Heat resistant glass
Glass is an inorganic substance. It is characterized by the properties of a solid, in the molten state it is a super-viscous fluid. Its fragility, strength, density and heat capacity vary greatly and depend on impurities.
Recently, materials have been developed that have non-typical properties for glass, for example, refractoriness. The main parameter that distinguishes heat-resistant glass from other glasses is the temperature at which it retains its properties. It withstands heating even at 1000 degrees Celsius, while its "colleagues" crack already at 80 degrees.
Refractoriness is affected by the composition and thickness of the material. If the glass is thick and contains a large proportion of alkaline oxides, then it will be durable. The most resistant heat-resistant glass is quartz. It withstands large temperature differences and has a high boiling point (2230 degrees).
Production of heat resisting glasses
Typically, glass is a mixture of several components. For standard material, quartz sand, lime and soda are taken. They are heated to very high temperatures (from 1700 degrees), which is why they melt and mix with each other. After this, the mixture is poured into molten tin (they do not mix due to the difference in density), and then gradually cool.
To give the necessary properties, other substances are added to these components. To make heat-resistant glass, various oxides are used. So, borosilicate material contains boron oxide, and silica contains silicon oxide.
It will have additional durability if several layers are used. To do this, he is allowed to cool completely. Finished sheets are ground, cleaned and cut to the required size. Then several sheets of glass are glued together with a special polymer. The final touch is the burning of a glass “sandwich” at 660-680 degrees.
Application
Heat resistant glass is popular in the kitchen. Ovens and utensils are made from it. A common product from this material is also a fireplace. Quartz glass is used in the manufacture of optical fibers, Fresnel lenses, crucibles, insulators, etc. Borosilicate glass is used for optical glasses, glassware, and reflector telescopes.
Refractory glassware has many advantages. It withstands even open fire, is durable. The material is quite inert and does not oxidize when heated, so it does not change the taste of the dish. It is not subject to corrosion and scale formation.
Of course, even heat-resistant glass has disadvantages. It does not respond well to a sharp increase or decrease in temperature. Dishes made of such material should not be placed on a large fire immediately after the freezer. In addition, refractory glass is not shockproof and should not be dropped.