Materials used around furnaces, heating elements and high-temperature processes must do more than tolerate heat. They must also respond predictably as temperatures change, maintain the necessary geometry and avoid introducing unnecessary complications into the process.
Fused quartz is well suited to many of these environments because it combines high-temperature capability with low thermal expansion. Those characteristics make it valuable in applications ranging from semiconductor processing and infrared heating to aerospace, steel, solar and laboratory systems.
Low Expansion Provides an Important Advantage
Most materials expand as they become hotter and contract as they cool. When connected materials expand at significantly different rates, stress can develop around joints, supports and mounting points.
Fused quartz expands relatively little as its temperature rises. This can help components maintain dimensional stability during thermal cycling. It does not, however, eliminate the need for thoughtful design. Interfaces with metals and other materials must still accommodate differences in expansion.
Uniform Heating Still Matters
High-temperature capability should not be mistaken for immunity to thermal stress. Localized heating can create large temperature differences across a quartz component. A tube positioned too close to a heating element, for example, may heat unevenly even if the surrounding furnace remains within the intended operating range.
Direct flame contact, unsupported sections and rapid cooling can also create stress. Large components may require particular attention to support, furnace placement and temperature distribution.
The operating environment should therefore be evaluated as a complete system. Maximum temperature is important, but so are heat location, ramp rates, hold times, cooling conditions and mechanical support.
Cleanliness Affects High-Temperature Performance
Surface contamination can accelerate devitrification, the gradual transition of quartz from its glassy state toward a crystalline condition. Oils, dust and residue left by bare hands can become more consequential at elevated temperatures.
Clean handling practices help protect the surface before installation and use. Quartz components should be handled with clean, appropriate gloves and stored with protective wrapping or end coverings in place whenever practical. Cleaning procedures should be selected for the application and performed by trained personnel using the required safety controls.
Design for the Real Process
At Technical Glass Products, we evaluate more than the nominal temperature printed on a drawing. Geometry, material grade, wall thickness, support conditions and the surrounding process can all influence performance.
Our technical downloads provide useful material and handling information, while our fabrication team can help translate operating requirements into a practical quartz component. In demanding thermal applications, that combination of material selection, design and proper use is what allows fused quartz to perform at its best.
