Physical properties of quartz glass

        Purity is an important indicator of quartz glass, which has a great influence on physical and chemical properties and performance, such as devitrification, high temperature strength, softening point, light conduction, thermal stability, chemical stability, radiation resistance, fluorescence properties, etc.; in addition, Quartz glass used in the semiconductor industry has more stringent requirements for purity, and trace impurities will seriously affect the electrical properties, life and integration of semiconductor materials. Since the purity of semiconductor materials is required to be controlled below the ppb order of magnitude, the quartz glass should be controlled in the ppm order of magnitude to meet the needs of the semiconductor industry. The segregation coefficient of B is close to 1, which is the most difficult to remove and is one of the most harmful impurities. Cu, Fe, Ti, etc. affect the minority carrier lifetime of semiconductors. K, Na, and Li are harmful impurities that cause micro-defects in single crystal materials.

        Ion diffusion and air permeability

The structure of quartz glass is very relaxed, and even at high temperatures, ions of certain gases are allowed to diffuse through the network, among which the diffusion of sodium ions is the fastest. This property of quartz glass is particularly important for users. For example, when quartz glass is used in the semiconductor industry as a high-temperature container or diffusion tube, due to the semiconductor material

        Quartz glass

        The material requires high purity, so the refractory material that is in contact with the quartz glass as the furnace lining must be subjected to high temperature and cleaning treatment in advance to remove alkaline impurities such as potassium and sodium, and then can be put into the quartz glass for use. Diffusion coefficients of various ions in quartz glass.

        Electrical Characteristics

        Quartz glass has high dielectric strength and extremely low electrical conductivity, that is, it can maintain high dielectric strength and resistance under high temperature, high pressure and high frequency, and there is almost no dielectric loss in the applied frequency band , so quartz glass is an excellent high temperature dielectric insulating material. At normal temperature, its resistance is equivalent to 10 times that of ordinary glass, the dielectric loss to all frequencies is very small, and the dielectric strength is high.

        Thermal properties

        The thermal expansion coefficient of quartz glass is small, 5.5×10-7/℃, which is only 1/12~1/20 of that of ordinary glass. The standard stipulates that the sample should be burned to 1200℃ and then quickly thrown into cold water. Repeating more than three times is not allowed. burst. Quartz glass can be made into a zero-expansion coefficient material after adding an appropriate amount of titanium, which has been used in laser technology, astronomy and cutting-edge technology.

        Mechanical behavior

        The mechanical properties of quartz glass are better than that of hard glass and ceramics, but the brittleness is poor. The theoretical calculation strength of quartz glass is very high, about 24 × 103 MPa, but the actual measured strength is dozens of times lower than this value. The strength of quartz glass increases with increasing temperature, reaching a maximum near the annealing temperature. The shear modulus, Young's modulus, damping, Poisson's ratio and failure modulus of quartz glass generally increase with the increase of temperature, while the hardness decreases with the increase of temperature.