The properties of quartz glass
Compared with ordinary glass, quartz glass has three excellent characteristics: heat resistance, corrosion resistance, and good thermal stability. The following is a more comprehensive summary of the properties of quartz glass:
- Optical performance
Quartz glass has a series of excellent optical properties. Compared with ordinary glass, high-purity quartz glass has properties ranging from far ultraviolet (160nm) to far infrared (5 μ m) The excellent light transmittance within the extremely wide spectrum of optical glass is not available. The excellent spectral transmittance and optical uniformity make quartz glass widely used in semiconductor lithography and precision optical devices. In addition, quartz glass has good radiation resistance, and radiation resistant quartz glass has been widely used in the "Shenzhou" series spacecraft.
- Mechanical properties
Quartz glass is similar to ordinary glass and belongs to brittle and hard materials. The strength parameters of quartz glass are influenced by many factors, including surface state, geometric shape, and testing methods. The compressive strength of transparent quartz glass is generally 490-1960MPa, tensile strength is 50-70MPa, flexural strength is 66-108MPa, and torsional strength is about 30MPa.
- Electrical performance
Quartz glass is an excellent electrical insulation material. Compared with ordinary glass, quartz glass has a higher electrical resistivity, with a resistivity of up to 1.8 at room temperature × 1019 Ω cm. In addition, quartz glass has a higher breakdown voltage (about 20 times that of ordinary glass) and lower dielectric loss. The resistivity of quartz glass slightly decreases with increasing temperature, while the resistivity of opaque quartz glass is lower than that of transparent quartz glass. 
- Thermal performance
The softening temperature of quartz glass is very high, and the long-term working temperature can reach 1000 ℃. In addition, the coefficient of thermal expansion of quartz glass is the lowest among common industrial glass, and its linear expansion coefficient can reach 5 × 10-7/℃, specially treated quartz glass can even reach zero expansion. Quartz glass also has excellent heat resistance, which means that it will not crack even after experiencing significant temperature differences repeatedly in a short period of time. These excellent thermal properties enable quartz glass to play an irreplaceable role in high temperatures and extreme working environments.
High purity quartz glass can be applied in chip manufacturing in the semiconductor industry, observation windows for industrial high-temperature furnaces, auxiliary materials for fiber optic manufacturing, high-power electric light sources, and space shuttle surfaces as insulation layers. The extremely low coefficient of thermal expansion also enables quartz glass to be used as lens materials for precision instruments and large astronomical telescopes.
- Chemical properties
The chemical stability of quartz glass is very good. Different from other commercial glass, quartz glass has extremely high chemical stability to water, so it can be used in water distillation vessels with extremely high requirements for water purity. Quartz glass has excellent acid and salt resistance, and does not react with most acid and salt solutions except for hydrofluoric acid, phosphoric acid, and alkaline salt solutions. Compared to acid and salt solutions, quartz glass has poor alkali resistance and will react with alkali solutions at high temperatures. In addition, quartz glass and most oxides, metals, non-metals, and gases do not react at conventional temperatures. The extremely high purity and good chemical stability enable quartz glass to be used in semiconductor manufacturing and other environments with high requirements for production conditions.