Quartz glasses: production features, GOST. Quartz glass optical: application

Glass - one of the most ancient materials, which is widely used in all areas of human practice due to a set of useful qualities and properties. During its existence (and this is more than 5 thousand years), its chemical formula has remained practically the same, only its qualities have changed.

Quartz glass

Over the years, people have sought to create glass more transparent and resistant to various destructive factors. As a result of this purposeful perfection, quartz glasses appeared - a completely new type of material with consciousness-damaging characteristics. Perhaps, it is this glass that will determine the direction of the further development of mankind. Quartz glass is the product of the melting of pure silicon oxide (SiO ₂ ). Unlike ordinary glass, this material is in an amorphous state, that is, it does not have an exact melting point, and when heated from a solid to a liquid state, it gradually passes. In many respects due to this property quartz, or silicate, glass has found so wide application in the industry.

Structure of quartz glass

The amorphicity of the material is explained by its structure, which is based on silicon-oxygen tetrahedra. The SiO ₂ molecules "bond" with each other due to the mutual attraction of oxygen atoms. Together they form three-dimensional grids, despite the fact that there is no strict order in the arrangement of the molecules relative to each other. That is why quartz glasses possess the properties of amorphous materials.

Silicate glass, like the usual, is obtained by melting the raw material. As such, pure silica - rock crystal, veined quartz, quartz sand, as well as silica obtained by artificial means can be used.

Differences of quartz glass from conventional

Depending on the type of raw material selected, certain properties of the final product are also determined. So, to obtain a crystal clear and transparent material use rock crystal.

The main difference between silicate glass and ordinary glass is the high melting point - more than 1500 ° C. At the same time, silicon oxide starts to emit intense light radiation in the visible spectrum, that is, it begins to glow.

Due to the amorphous structure of the raw material, the melting process can continue for a considerable time. Molten composition has a high viscosity, which does not allow it to staple or move. This makes it difficult to produce quartz glass with the same wall thickness.

Production features

In view of all these features, production of silicate glass is possible only on specialized equipment. In the smelters must be maintained a high temperature, and for the creation of glass products it is necessary to maintain a stream of open flame at a temperature of 1800 ° C and above.

Special requirements are also imposed on the production room - it must be sterile. A small number of foreign particles will inevitably lead to the fact that the finished quartz glasses will soon crack and lose their properties. Special qualities should be enjoyed by the production staff - glass blowers. They have to deal with extremely high temperatures - one error during work can lead to serious injuries, burns.

All the main glass blower tools are made of heat-resistant materials - granite, tungsten, which, among other things, are of great weight. Therefore, employees must be physically strong and enduring.

Properties of quartz glass

Silicate glass has low electrical conductivity, so it is often used as a dielectric in complex electrical appliances. The main useful properties, which quartz glasses possess, can be divided into three groups:

1. Thermal. Resistance to high temperatures (1200 С ^о ), high coefficient of temperature expansion (15 times higher than that of ordinary glass), which causes resistance to sharp and significant temperature fluctuations (in production, the product is cooled with a jet of ice water).
2. Chemical. Glass is chemically neutral, does not react with all alkalis and acids, except phosphoric and hydrofluoric acid (the reaction begins at temperatures above 300 ° C).
3. Optical. The refractive index of quartz glass is 150 times lower than that of conventional glass (n _e = 1.46). Due to this, it flawlessly passes not only sunlight and ordinary light, but also does not delay either infrared or ultraviolet radiation.

All these properties allow the use of quartz glass as a building material, as well as for the production of laboratory glassware, optical instruments, electrical equipment, heat-resistant refractory materials. One of the main areas of its application is the production of optical fibers.

Optical quartz glass

Depending on the technology used in the production of quartz glass can be opaque and transparent. In the first case, its structure will contain a large number of gas bubbles, which intensively scatter light. Transparent glass, or quartz optical glass, as it is also called, is absolutely homogeneous, does not contain bubbles. Due to this feature, the material is used in the production of optical cables for high-speed data transmission, optical lenses and prisms.

Stamps and optical glass series

There are several brands of optical glass: KU-1, KI, and KV. Products differ among themselves by the ability to transmit visible, ultraviolet and infrared radiation. The most transparent is the KI glass - it is capable of transmitting light at a wavelength of 2600-2800 nm, the least transparent - KV. Depending on the raw materials used, different light transmission capacities can have quartz optical glass. GOST 15130-86 contains information about three series:

• 0 - material used under normal operating conditions;
• 100 - glass, resistant to ionizing radiation of insignificant force;
• 200 - raw materials, which can be used in conditions of intense ionizing radiation.

The make and series of glass form the cipher of production. It is applied in the production and determines the specific type of glass. In our country there is no single system of encryption, therefore each enterprise designates its products according to its own understanding.

Application area

A large number of various products are made from silicate glass. In scientific and industrial laboratories, quartz glass tubes are in demand, which are used to measure liquid levels, manufacture electric heaters, conduct chemical reactions and store aggressive substances.

Extensive use in the production received and opaque glass. It is used wherever control of liquid products is required at high temperatures and, due to low cost, is used universally.

Optical glass is used in shipbuilding and rocket construction, mainly for the production of lighting devices. In petrochemical plants, this material is valued for its high resistance to chemicals and is used to control aggressive liquids. In aircraft, they glazed the cabin, and also used as a thermal insulation.

Manufacturers produce products in accordance with the requirements of GOST 22291-83. Quartz glass, tubes, windows, prisms, lenses and other products are manufactured both massively and individually.