Zinc sulfide
ZnS
Zinksulfid (ZnS) is a material used for optical components for the infrared range. Unlike other materials for the infrared range such as germanium or silicon, zinc sulfide is also transparent in the visible spectral range. ZnS is produced by chemical vapor deposition (CVD). In this process, the material is divided into two grades, which differ in their transmission properties:
Infrared quality (FLIR) is a polycrystalline material that is used as it was deposited during manufacture. It is used for optics in the wavelength range between 0.4 µm and 12 µm.
Multispectral quality (ms) is posttreated in a process step after growth to eliminate microscopic pores/cavities and defects that occur during the CVD process. This improves the transmission properties of the material, allowing the multispectral zinc sulfide to be used in the wavelength range between 0.35 µm and 14 µm. The multispectral zinc sulfide is used for windows or domes that require a single aperture or beam path for some wavelength bands, such as in visual cameras, medium- and long-wavelength detectors, and laser-based rangefinders. Multispectral zinc sulfide is also used in the field of temperature measurement.
Optical and spectral properties | FLIR ZnS | Multispectral ZnS |
---|---|---|
Transmission range in µm (minimum 10%) | 1‐14 | 0,35‐14 |
Transmission range in µm (minimum 50%) | 1‐13 | 0,37‐13 |
Refractive index @633nm | 2,351 (2,192 @10,6µm) | 2,351 (2,201 @10µm) |
Reflection losses in % at 1 surface | 14 @10µm
| 14 @10µm
|
Reflection losses, % for two surfaces | 24,6 @10,6µm
| 24,7 @10,6µm
|
dN/dT in 1/K | -43 · 10-6 @3,39µm
| -38,7 · 10-6 @3,39µm
|
Physical properties | FLIR ZnS | Multispectral ZnS |
---|---|---|
Density in g/cm3 | 4,08
| 4,09
|
Melting point in °C | 1827 | 1827 |
Specific heat capacity in J/(kg · K) | 469
| 515
|
Thermal conductivity in W/(m · K) | 16,7 @296K | 27,2 @298K |
Thermal expansion in 1/K | 6.6 · 10-6 @273K
| 6,5 · 10-6 @273K
|
Dielectric constant | 88
| |
Solubility in water in g/100g | insoluble | insoluble |
Mohs hardness | 3,5‐4
| |
Knoop hardness in kg/mm² | 160
| 160
|
Material type | polycrystalline, synthetic
| polycrystalline, synthetic
|
Crystal type | cubic, zincblende structure | cubic, zincblende structure |
Crystal structure | Fm3m
| cF8 |
Lattice constant in Å | a = 5,42
| a = 5,42
|
Elastic coefficient in GPa | C11 = 102 C12 = 64,6 C44 = 44,6 | |
Young's Modulus (E) in Gpa | 74,5
| 74,5
|
Apparent elastic limit in MPa | 103,4
| 68,9 |
Poisson's ratio | 0,29 | 0,28 |
Spectral properties | |
---|---|
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Optical Properties | FLIR ZnS | Multispectral ZnS |
---|---|---|
Transmission range in µm @10% min. | 1 - 14 | 0.35 - 13 |
Transmission range in µm @50% min. | 1 - 13 | 0.37 - 13 |
Refractive index | 2.192 @10.6µm | 2.20084 @10µm |
Reflection losses in % at 1 surface | 14 @10µm | 14 @10µm |
Reflection losses in % at 2 surfaces | 24.6 @10.6µm | 24.7 @10.6µm |
dn/dT in 1/K | 43 · 10-6 @3.39µm | 38.7 · 10-6 @3.39µm |
Physical Properties | FLIR ZnS | Multispectral ZnS |
---|---|---|
Density in g/cm³ | 4.08 | 4.09 |
Melting point in °C | 1827 | 1827 |
Specific heat capacity in J/(kg · K) | 469 | 515 |
Thermal Conductivity in W/(m · K) | 16.7 @296K | 27.2 @298K |
Thermal Expansion in 1/K | 6.6 · 10-6 @273K | 6.5 · 10-6 @273K |
Dielectric constant | 8.393 | 88 |
Solubility in water in g/100g | unsoluble | unsoluble |
Mohs hardness | 3.5 - 4 | |
Knoop hardness in kg/mm² | 160 | 160 |
Material type | Polycrystalline, synthetic | Polycrystalline, synthetic |
Crystal type | cubic, Zincblende structure | |
Crystal structure | F43m | F42m |
Lattice constant in Å | a = 5.67 | |
Elastic coeficients in GPa | C11 = 102 C12 = 64.6 C44 = 44.6 | |
Young's Modulus (E) in GPa | 87.6 | 33 |
Shear Modulus (G) in GPa | 80.41 | |
Bulk Modulus (K) in GPa | 63.1 | |
Rupture Modulus in MPa | 68.9 | |
Apparent elastic limit in MPa | 103.4 | 68.9 |
Poisson ratio | 0.29 | 0.28 |
Spectral Properties | |
---|---|
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