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http://www.stemmerich.com
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BK-7
DESCRIPTION
| BK-7 is a barium borosilicate glass known for its high transmission and clean, clear appearance. It is a standard by which many other glasses are compared, both optical and non-optical types. |
AVAILABLE THICKNESSES, SIZES
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BK-7 is produced in strips and blocks up to about 14" wide and about 2.8" thick. We can fabricate them to any smaller size. Larger strips and sizes are usually available upon request.
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PROPERTIES
| Refractive Index: | nd (λ = 588 nm) = 1.51680 |
| Internal Transmittance @ 5 mm thick: |
310 nm 59% | 365-1529 nm 99%+ |
| 335 nm 95% |
2325 nm 89%
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| Mechanical and Thermal: |
Density | 2.39 g/cm3 |
| Thermal Coefficient of Expansion (20-300°C) = 83 x 10-7 | ||
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Melting Point
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532°C | |
| Microhardness | 610 | |
| Chemical: |
Climatic Resistance
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Class 2
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Stain Resistance
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Class 0
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Acid Resistance
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Class 1 | |
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Alkali Resistance
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2.0
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Phosphate Resistance
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2.3
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APPLICATIONS
| Optical substrates, image-forming optics, electronics, laboratory and coating substrates. |