Glass is classified by main components:
Glass can be divided into non-oxide glass and oxide glass according to its main components. There are few varieties and quantities of non-oxide glasses, mainly chalcogenide glasses and halide glasses. Oxide glass can be divided into silicate glass, borate glass and phosphate glass. Oxide glasses are usually divided into:
1 timely glass
The silica content of the timely glass is more than 99.5%, which has low thermal expansion coefficient, high temperature resistance, good chemical stability, ultraviolet and infrared light transmittance, high melting temperature and high viscosity, and is not easy to form. Timely glass is mostly used in semiconductor, electric light source, optical communication, laser and other technologies and optical instruments.
2. High silicon glass
The silica content of high silica glass is about 96%, and its performance is similar to that of timely glass.
3. soda-lime glass
Soda-lime glass mainly contains silicon dioxide, and also contains 15% sodium oxide and 16% calcium oxide. Low cost, easy molding, suitable for mass production, and the output accounts for 90% of practical glass. Soda-lime glass can be used to produce glass bottles, flat glass, utensils, light bulbs and so on.
4. Lead silicate glass
Lead silicate glass is mainly composed of silicon dioxide and lead oxide, which has unique high refractive index and high volume resistance and good wettability with metals. It can be used to manufacture light bulbs, vacuum tube cores, crystal glassware drawings (such as jazz series crystal tableware), flint optical glass, etc.
5. Aluminosilicate glass
Aluminosilicate glass is mainly composed of silica and alumina, which has a high softening and deformation temperature. It is used to make discharge bulbs, high-temperature glass thermometers, chemical combustion tubes and glass fibers.
6. borosilicate glass
Also known as heat-resistant glass or hard glass, with silicon oxide and barium oxide as the main components, it has good heat resistance and chemical stability. Borosilicate glass was invented in 19 12 with the trade name Pyrex.
It is the first kind of glass material with good high temperature resistance and thermal shock resistance (such as glass jewelry made of borosilicate glass material). Borosilicate glass can be used to make coffee pots, stoves, laboratory glassware, chandeliers (such as chandeliers made of heat-resistant glass) and other equipment working in high temperature environment. It has strong acid resistance, chemical corrosion resistance and low thermal expansion coefficient, so it is used to manufacture lenses and other precision instruments for astronomical telescopes. In addition, borosilicate glass can also be used as reinforcing fiber of resin.
7. Phosphate glass
Phosphate glass is mainly composed of phosphorus pentoxide, which has low refractive index and small dispersion and is used in optical instruments. The basic characteristics of glass are as follows:
(1) strength
Glass has weak tensile strength and strong compressive strength. Like ceramics, glass is a brittle material.
(2) Hardness
The hardness of glass is higher than that of ordinary metal, so it can't be cut with ordinary tools. Abrasive, grinding and other processing methods can be selected according to the hardness of glass.