Fused Quartz - Applications

Applications

Specially prepared fused silica is the key starting material used to make optical fiber for telecommunications.

Because of its strength and high melting point (compared to ordinary glass), fused silica is used as an envelope for halogen lamps, which must operate at a high envelope temperature to achieve their combination of high brightness and long life.

The combination of strength, thermal stability, and UV transparency makes it an excellent substrate for projection masks for photolithography.

Its UV transparency also finds uses in the semiconductor industry; an EPROM, or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off, but which can be erased by exposure to strong ultraviolet light. EPROMs are recognizable by the transparent fused quartz window which sits on top of the package, through which the silicon chip is visible, and which permits exposure to UV light during erasing.

Due to the thermal stability and composition it is used in semiconductor fabrication furnaces.

Fused quartz has nearly ideal properties for fabricating first surface mirrors such as those used in telescopes. The material behaves in a predictable way and allows the optical fabricator to put a very smooth polish onto the surface and produce the desired figure with fewer testing iterations. In some instances, a high-purity UV grade of fused quartz has been used to make several of the individual uncoated lens elements of special purpose lenses including the Zeiss 105mm f/4.3 UV Sonnar, a lens formerly made for the Hasselblad camera, and the Nikon UV-Nikkor 105mm f/4.5 (presently sold as the Nikon PF10545MF-UV) lens. These lenses are used for UV photography, as the quartz glass has a lower extinction rate than lens made with more common flint or crown glass formulas.

Fused silica as an industrial raw material is used to make various refractory shapes such as crucibles, trays, shrouds, and rollers for many high-temperature thermal processes including steelmaking, investment casting, and glass manufacture. Refractory shapes made from fused silica have excellent thermal shock resistance and are chemically inert to most elements and compounds including virtually all acids, regardless of concentration, except hydrofluoric acid which is very reactive even in fairly low concentrations. Translucent fused silica tubes are commonly used to sheathe electric elements in room heaters, industrial furnaces and other similar applications.

Thanks to its low mechanical damping at ordinary temperatures, it is used for high-Q resonators, in particular, for wine-glass resonator of hemispherical resonator gyro (HRG).

Quartz glassware is occasionally used in chemistry laboratories when standard borosilicate glass can not withstand high temperatures; it is more commonly found as a very basic element, such as a tube in a furnace, or as a flask, the elements in direct exposure to the heat.