HHV has been a solution provider of infrared technology, including
- Gold coating on ZnS domes
- AR Coatings on Germanium
- Diamond Like Carbon Coatings, etc.
GOLD COATINGS ON ZnS DOMES
ZnS domes are used as impact sensors on missiles. As these missile speeds up, the force of acceleration triggers the arming mechanism. When the missile makes contact with the target, an impact sensor sets off the war head. HHV has developed Gold coatings on ZnS domes and it has the following following properties;
- Corrosion resistant
- Excellent adhesion
- Low resistance <12Ω
INFRARED ANTI-REFLECTION (AR) COATINGS : AR COATINGS ON GERMANIUM, 8 - 12 micron
Passive night vision systems that works in FIR region, images the scenes based on the surface temperature by detecting the infrared radiation that emanates from the objects and surrounding environment. Thermal imaging has applications in defense, industrial security, transportation, cancer detection, body scans, and hot-spot detection. Germanium is the widely used material in 8-12 microns band.
High efficiency broad band AR coating developed by HHV offers high transmission and very low reflection in the band 8-12 micron And the coating contains no radioactive materials.
This coating is designed to meet durability requirements of the following MIL Specifications:
- Adhesion : MIL-C-48497, Tape test
- Humidity : MIL-C-48497 24hrs, 49oC, 95-100% relative humidity
- Moderate Abrasion: MIL-C-48497, Moderate, 50 strokes with cheese cloth
DIAMOND LIKE CARBON (DLC) COATINGS
DLC coatings are used in thermal Imaging applications where harsh environments may cause damage to standard AR coatings.
The features of the DLC coating developed at HHV are;
- Refractive index: 1.9
- Guaranteed adhesion: Withstands cellulose tape as per MIL-M-J3508C
- High optical transmission: 88% Transmission in the region 8-12 microns
- High Hardness: > 8 GPa
- Resistance to wear abrasion: withstands severe eraser test for 20 complete cycles as per MIL-C-675C
- Humidity: Coating shows no deterioration when exposed to a temperature of 48 Degree C and 95% to 100% RH for a minimum of 24 hours as specified in MIL-C-675
- Solubility: Coating shows no deterioration when immersed in a solution of water and salt for 24 hours as per MIL-C-675C
- Salt Spray: Coating shows no deterioration when subjected to a salt spray fog test in accordance with ASTMB 117-73 for a continuous period of 24 hours as per MIL-C-675C
- Temperature cycle: Coating shows no deterioration when exposed to ambient temperatures of -80 F and 160 F for a period of 5 hours at each specified temperatures as per MIL-M-13508
- Chemical inertness: The coating is inert to corrosive attack by acids like HCL
- Windscreen viper test: Coating withstands when exposed to 5000 revolutions of a wiper blade under 40 grams load using a sand water mixture
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