Crystal Industry Innovation
Introduction
Quartz Glass is made by melting Silica with high purity and it is divided with two types, transparent and opaque. The transparent product made by Quartz was called Quartz Glass and the opaque product made by sand was called Silica Glass before, but the both are called Fused Quartz nowadays.
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[Opaque Glass]
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[Transparent Glass]
One of advantage of Quartz Glass is that it contains very little impurities because it is made by Silica with high purity in high temperature. Because of this, it is used for the equipment of Semiconductor industry, Silicon refinery, etc. More, it contains less gas than other materials do and can keep the stability in a high temperature, so it is also used for the semiconductor process in high temperature.
The Coefficient of Thermal Expansion of Quartz Glass(5.5×10-7cm/cm℃) is far less than those of other materials, and it is just one-sixth of ceramics or hard glass and one-two hundred of sheet glass. So, Quartz Glass has high resisting property against rapid heating or freezing. Specific Heat is 890~1,140J/Kg( 20~1000 ), and Thermal Conductivity (0℃~1.3w/mk , 100℃~1.5w/mk) is rather low. Specific Heats of transparent and opaque glasses are almost same, but Thermal Conductivity of opaque glass is rather lower. It is nonconductor which has less alkali which can generate the electrical conduction, and it has less dielectric loss against all frequencies.
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[Fused Quartz Process]
Flexural strength and tensile strength differs sharply according to the surface. But it tends to be weaker if the size is bigger. Elasticity, Flexural strength and tensile strength become stronger with temperature increase and they are strongest in 800~900 ˚C. In more than 1100 ˚C, viscosity of Quartz Glass itself falls down, so there may be twisting or distorting after a long time.
As for UV penetration ratio, it shows high penetration ratio in low frequencies. Synthetic Quartz is well used for the Ｏrganic Electro Luminescence Display due to its good penetration ratio.