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BryCoat Tungsten Disulfide (WS2) Dry Lubricant Coatings

Composition WS2.  [>99% purity.]  Tungsten Disulfide or Tungsten Disulphide or Tungsten (IV) Sulphide
Binder No binder used.  No curing cycle required.
Appearance Silver-gray.
Thickness 0.5 microns.  See the thickness conversion chart.
Uniformity Coating conforms uniformly to the substrate.  No buildup occurs on corners (unlike plating operations). 
Hardness Approx. 30 HRc.
The coating forms a mechanical-molecular interlock to the substrate that will not flake, blister, chip or peel.  
The presence of WS2 dust on the surface of the coated product is normal and does not indicate delamination of the coating from the substrate.  This surface dust is simply excess coating material that was not bonded to the part.  If this dust can not be tolerated, please specify this to a BryCoat applications engineer to arrange for cleaning of the part after coating.  Generally, this dust is not detrimental, in fact, it is an additional source of lubrication in the system.
WS2 provides extremely low friction against steels, carbides, TiN, ceramics, platings, plastics, etc.
The dynamic coefficient of friction of WS2 coating against steel is about .03. Static coefficient of friction of WS2 coating against steel is about .07. This corresponds to lower friction than teflon, graphite, MoS2, and diamond.  
The coefficient of friction is a system property, not a material property.  It is dependant on many factors such as material, counter-material, lubrication, temperature, speed, loading force, surface finish, surface finish of the counter-material, and type of motion (reciprocating, rotating).   Published values can have large variations. 
Non-stick WS2 is an excellent non-stick surface against most other materials.  It is used to aid release of parts from plastic molds and reduce drag of plastic through the mold for faster and more complete fill.
Toxicity Non-toxic. 
Service Temperature -450°F (-270°C) to 1200°F (650°C) in air, -305°F (-188°C) to 2400°F (1300°C) in high vacuum.
Melting Point 1480°C (decomposition at 1250°C)
Deposition Temperature Ambient (room temperature).
Electrical Resistivity Does not insulate parts from electicity
Chemical Resistance Fairly inert.  Not compatible with strong oxidizing agents, strong caustics, or strong acids.
LOX Compatibility Insensitive to detonation by or in the presence of oxygen
Thermal Conductivity Coating is too thin to significantly impact thermal conduction.
Density 7.4 g/cm3.
Molecular Weight 248.02
Crystal Structure Hexagonal
Young's Modulus, Modulus of Elasticity N/A
Poisson's Ratio N/A
Heat of Formation N/A
Band Gap Unknown
 
While BryCoat believes that the above properties are accurate, no warranty is made on the accuracy of the data.  The customer is responsible for testing properties that are critical to their application and for determining the suitability of the coating for the application.
 
Please let us know if you have any additional data on physical properties of thin film coatings.

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BryCoat Inc.
727-490-1000      800-989-8788      Fax: 727-490-0233
207 Vollmer Avenue      PO Box 1976      Oldsmar, Florida 34677      USA

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While BryCoat believes that the information contained in this website is accurate, no warranty is made on the accuracy of the data. The customer
is responsible for testing properties that are critical to their application and for determining the suitability of any coating for the application.