Translucent and fragile substance made by melting glass silty clay. Glass, usually borate from alkaline and alkaline earth silicates, also contains borate and aluminates.
The most widespread belief in the glass of the invention is the fact that it has a very long history. It is assumed to be in bronze age in 3000 years.
The Mosaic Glass was made by artisans of Alexandria origin in Ptolemaios in Egypt, colored glass It is known that decorative patterns are formed with fragments. Glass blowing art of BC It is known to be spread by Syrian glass craftsmen in the 1st century.
15. In the twentieth century, the crystal glass in Venice was invented with the name Cristallo. In 1675, Venetian glass master George Ravenscroft cama invented the lead crystal glass by adding lead oxide.
The glass levan was invented on March 25, 1902.
Glass jars and bottles were invented by Michael Owen on August 2, 1904, for a “glass forming machine”. Irving W. Colburn has made a series of production of glass windows and patented sheet glass pulling machine.
Other Glass Information h2>
The glass has no melting point. The glass has no melting point. It softens when heated and can be given the desired shape. Hot forming can be done at 800-1300 ° C. The glass starts to soften above about 500 ° C. Since the expansion coefficient of silica glass is very low, it is resistant to temperature changes. However, other glasses are not resistant to temperature changes, as the expansion coefficient is large. No glass can be heated as desired. In particular, it can not be cooled. If a glass is welded together with a metal, the expansion coefficient of the metal and glass must be the same. The breaking load of the windows is 4-10 kg / cm2, the resistance against the pressure is 60-120 kg / mm2 and the elastic modulus is 4500-10.000 kg / mm2. Hardness (determined by drawing test) is around 200 in ordinary glass. As the silica ratio increases, the hardness of the glass can increase to 270. Density is around 2,4-2,6 in common glass; 3-3.8 g / cm3 in leaded glass. The electrical conductivity of glass is very low and it is electrolytic type. Electric conductivity increases with temperature. Adult glass is impervious to ultraviolet rays. Colored glasses containing manganese only pass infrared rays.
Glasses have increased resistance to austenite with silica and aluminum. But it falls with alkaline ratio. The glasses are not much affected by water, but the water under pressure can quickly erode the vapor. Fluoride acid (HF) is not affected by any acid other than acid.