What are the different types of fused quartz?
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Types of Fused Quartz
Fused quartz is a material made by melting high purity silica in various forms. It is used extensively in applications that require high thermal resistance, optical clarity, and purity. There are several types of fused quartz, each tailored for specific applications and properties.
1. Type I Fused Quartz
Definition: Type I fused quartz is produced from a high purity source material, making it suitable for applications requiring minimal inclusions and bubbles.
Applications: It is commonly used in the semiconductor industry, UV transmission systems, and high-performance optical components.
2. Type II Fused Quartz
Definition: This type is manufactured from naturally occurring quartz crystals and is slightly less pure than Type I. It contains a higher level of hydroxyl (OH) groups.
Applications: Type II is often used in applications where UV transparency is not as critical, such as in lamp tubing and various chemical processing equipment.
3. Type III Fused Quartz
Definition: Type III is a synthesized mixture of silica and up to 2% other oxides, providing specific properties not found in natural quartz.
Applications: Its applications include photomask substrates, optical flats, and certain types of optical fibers where specific doping is required.
4. Synthetic Fused Silica
Definition: Synthetic fused silica is produced through a chemical synthesis process, resulting in extremely high purity and virtually no hydroxyl content.
Applications: It is ideal for use in the semiconductor industry, high-power laser systems, and in the manufacture of lenses and mirrors requiring the highest level of optical clarity.
Comparison Table
| Type | Purity | Hydroxyl Content | Applications |
|---|---|---|---|
| Type I | High | Low | Semiconductor, UV optics |
| Type II | Medium | Medium | Lamp tubing, Chemical processing |
| Type III | Varied with dopants | Low to Medium | Photomask substrates, Optical flats |
| Synthetic | Very High | Very Low | Semiconductor, High-power lasers |
Each type of fused quartz serves a unique set of applications, chosen based on its specific properties such as purity, hydroxyl content, and resistance to thermal and chemical stresses.