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Basic Science
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Glass powders consist of various glass compositions ground down into very small particles. SCHOTT offers particle sizes of > 30 µm down to as low as 0.4 µm (D50).
SCHOTT’s Glass Powder Technology is based on the following process steps:
- Melting: Practically all melting is done in-house. The choice of melting technology depends on the composition and quality requirements of the individual glass type. Far more than 100 different glass compositions that are developed in-house can be offered as powders.
- Grinding: Depending on the desired grain size and distribution, different dry and wet grinding technologies are used. These include SCHOTT’s patented UF Ultrafine technology for grain sizes down to 0.4 µm, mostly used in the Dental Field.
Further processing capabilities include the following:
- Silane coating of dental glasses is done after grinding.
- Granulation: Sealing or solder glasses are mixed with an organic binder and spray dried into relatively round agglomerates of glass. This can be easily pressed and sintered into glass preforms of various shapes.
- Paste: After grinding, glass powders are mixed with an organic binder to manufacture a paste with defined viscosity. It can be screen-printed or dispensed by the customer.
Advantages of the Technology
SCHOTT controls the entire process chain from development and selection of raw materials to grinding and further processing:
- With more than 125 years of melting experience and the availability of different melting technologies, excellent purity and batch-to-batch repeatability is ensured.
- Different grinding technologies ensure grain size distribution and purity is exactly geared to the individual application. SCHOTT continuously optimizes grinding technologies, both in-house as well as with external development partners.
- SCHOTT UF Ultrafine technology offers contamination-free grinding with extremely narrow distribution down to grain sizes of 0.4 µm (D50).
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Applications
Glass powders are used in a variety of fields. Examples:
- So called “Passivation Glasses” protect the sensitive p/n junctions of semiconductors and serve as packaging element at the same time.
- Sealing glasses are matched exactly to the needs of GTMS and are mostly processed into pastes or preforms before being joined with other materials.
- Dental glasses are used for highly aesthetic composite filling materials.
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SCHOTT Careers
SCHOTT Careers