A quartz crucible is a cup or bowl-shaped container made from quartz glass. It is used for holding and heating materials in laboratories and in certain industrial applications like the manufacture of silicon wafers for microchips and in solar cell industry. A quartz crucible can be very small or as large as 3 feet (0.9 m) in diameter. The crucible can also be made with a variety of different formulations of quartz glass, depending on usage.
Glass made from pure crushed quartz is called quartz glass. It is durable and heat resistant and highly desirable as a glass for laboratory equipment, including beakers, flasks, and crucibles. It is also chemically inactive, which is also useful in laboratory settings. A quartz crucible has another property that makes it suitable for heating materials. It resists expansion and contraction due to changes in temperature.
Quartz glass is naturally clear, more so than regular glass. It can be made opaque, however, with certain additives, and quartz glass of this type is sometimes used for making crucibles. Opaque quartz glass is usually white or off white in color, although other colors are possible. A quartz crucible is typically thick walled and both heavier and stronger than a typical beaker, flask or other glass laboratory equipment and often lacks a rolled rim as is often found on many other types of laboratory glass. A quartz crucible may have a close fitting lid.
Beyond their use in laboratories, quartz crucibles are widely used in the microchip and solar cell industries. The chemical composition of quartz makes containers of this type ideal for the creation of large silicon wafers of extremely high quality and crystalline uniformity. These wafers are used to make microchips, and a similar process is used to make solar cells. Quartz crucibles are sometimes used in the refining of certain metals because they are able to withstand the high temperatures found in the refining process.
A quartz crucible can vary greatly in physical dimensions. They can be very small, holding only a few milliliters, or very large, like those used in the microchip and refining industries. Shapes can vary widely as well, depending on the usage. A quartz crucible may be cylindrical, tall, and narrow, or a short, squat, wide shape. They may be tapered, with sides having a straight or curved profile. The glass can vary in thickness, depending on the intended use and can be as much as 2 inches (5 cm) or more thick.