Zinc Sulphide Multispectral (Zinc Sulfide) (ZnS)

♦ Zinc Sulphide Multispectral (ZnS) Data Sheet ♦ Zinc Sulphide Multispectral (ZnS) Guide to Cutting

♦ Zinc Sulphide Multispectral (ZnS) MSDS

ZnS Multispectral (water-clear) is used for IR windows and lenses in the thermal band (8 to 14 μm) where maximum transmission and lowest absorption is required. Also selected for use where visible alignment is an advantage.

Transmission Range :	0.37 to 13.5 μm
Refractive Index :	2.20084 at 10 μm (1)
Reflection Loss :	24.7% at 10 μm (2 surfaces)
Absorption Coefficient :	0.0006 cm^-1 at 3.8 μm
Reststrahlen Peak :	30.5 μm
dn/dT :	+38.7 x 10^-6 /°C at 3.39 μm
dn/dμ :	n/a
Density :	4.09 g/cc
Melting Point :	1827°C (See notes below)
Thermal Conductivity :	27.2 W m^-1 K^-1 at 298K
Thermal Expansion :	6.5 x 10^-6 /°C at 273K
Hardness :	Knoop 160 with 50g indenter
Specific Heat Capacity :	515 J Kg^-1 K^-1
Dielectric Constant :	88
Youngs Modulus (E) :	74.5 GPa
Shear Modulus (G) :	n/a
Bulk Modulus (K) :	n/a
Elastic Coefficients :	Not Avalailable
Apparent Elastic Limit :	68.9 MPa (10,000 psi)
Poisson Ratio :	0.28
Solubility :	65 x 10^-6 g/100g water
Molecular Weight :	97.43
Class/Structure :	HIP polycrystalline cubic, ZnS, F42m

To download this data or our MSDS safety data sheet as a pdf, please click on the links at the top of the page. To expand the transmission graphs, please click on the image.

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No = Ordinary Ray

µm	No	µm	No	µm	No	µm	No	µm	No
0.4047	2.54515	0.6678	2.34033	1.5296	2.27191	9.000	2.21290
0.4358	2.48918	0.7065	2.33073	2.0581	2.26442	10.00	2.20084
0.4678	2.44915	0.780	2.31669	3.000	2.25772	11.25	2.18317
0.480	2.43691	0.7948	2.31438	3.500	2.25498	12.00	2.17101
0.5086	2.41279	0.8521	2.30659	4.000	2.25231	13.00	2.15252
0.5461	2.38838	0.8943	2.30183	4.500	2.24955
0.5876	2.36789	1.014	2.29165	5.000	2.24661
0.6438	2.34731	1.1287	2.28485	8.000	2.22334

(1) Refractive Indices of Zinc Sulfide. Mary Debenham (NPL) Applied OPtics / Vol 23, No 14 / July 1984

Zinc Sulphide is produced by synthesis from Zinc vapour and H₂S gas, forming as sheets on Graphite susceptors. Zinc Sulphide is microcrystalline in structure, the grain size being controlled to produce maximum strength. Multispectral grade is then Hot Isostatically Pressed (HIP) to improve the mid IR transmission and produce the visibly clear form. Single crystal ZnS is available, but is not common.

Zinc Sulphide oxidizes significantly at 300°C, exhibits plastic deformation at about 500°C and dissociates about 700°C. For safety, Zinc Sulphide windows should not be used above 250°C in normal atmosphere.

References:

(1) Refractive Indices of Zinc Sulfide in the 0.405 - 13µm range. Mary Debenham (NPL) Applied OPtics / Vol 23, No 14 / July 1984