What Is Fused Quartz?

What Is Fused Quartz?

Fused quartz is a non-crystalline glass containing almost pure silica in an amorphous form.fused quartz It can be fabricated through flame or vapor phase hydrolysis of a silicon halide. It is manufactured to various purity specifications, for several specific uses.

It has excellent chemical resistance and is inert to most acids, except for hydrofluoric acid (HF). It is also resistant to reactive gases such as argon, nitrogen, and chlorine. It is a good choice for a wide range of industrial applications where high temperatures are required.

A number of refractory shapes are made from fused quartz for use in thermal processes such as steelmaking, investment casting, and glass manufacturing. These include crucibles, trays, shrouds, and rollers. They are chemically inert to virtually all elements and compounds, and have very high thermal shock resistance. They are used in electric furnaces and other industrial heating systems.

The crystalline structure of quartz contains strong covalent bonds between silicon and oxygen atoms; each molecule is tetrahedral in shape with an ordered network of SiO4 molecules forming the body-centered crystal. It is metastable and amorphous, meaning that it changes its shape as it cools.

Before the fusion process begins, the quartz is reduced in size through crushing and milling. The particles are then shaped to a size that can be fed into the refractory crucible for fusion. The resulting quartz is melted into a liquid state and collected for further processing.

During this fusion step, the strong covalent bond between silicon and oxygen is broken, converting the crystalline quartz into a vitreous material. The hydroxyl (OH) groups from water become embedded in the quartz glass; this may cause a reduction in infrared transmission and may lower the thermal stability of the quartz glass.

Because of this, IR-grade fused silica must have very low levels of OH to be useful for IR optical applications. The OH content can be determined by the annealing process.

It is important to select the correct type of fused quartz for the application, considering a number of factors such as the wavelength to be transmitted, the thermal treatment, and the amount of moisture in which the material will be exposed at elevated temperatures. The OH content of a material affects infrared transmittance and attenuation, but also affects the material's viscosity and its ability to be cooled down.

This is why it is important to choose the right oxidation method for a particular application, and to ensure that the resulting material meets the desired purity standards. In addition, it is crucial to have an appropriate refractory coating for optimal results.

SGP's CNC milling, cutting, drilling, and lapping capabilities can be utilized to manufacture a range of refractory shapes from fused quartz. These can be crafted into custom sizes and surface finishes to meet the requirements of an application.

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