What is WS2_ - WS2 Oil

06/05/2015 WhatisWS2?WS2Oil.Yourtungstendisulfidesupplier.

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WS2 Oil. Your tungsten disulfide supplier.

1.What is Tungsten disulfide (WS2 )? Tungsten Disulfide is one of the most lubricious materialsknown to science. With Coefficient of Friction (dynamic at 0.07, static at 0.03), it offers excellentdry lubricity unmatched to any other substance. It can also be used in high temperature andhigh pressure applications. It offers temperature resistance from 450o F (270o C) to 1200o F(650o C) in normal atmosphere and from 305o F (188o C) to 2400o F (1316o C) in Vacuum. Loadbearing property of coated film is extremely high at 2000Mpa (300,000 psi).When being applied tosolid lubricity of spaceflight, only WS2 can endure such high temperature 270~1300 in cosmicspace. Thus, it is extensively used by NASA spaceflight, aviation, military etc. as lubricantmaterial with high performance.

2. Lubricating Mechanism of Tungsten Disulfide Why WS2 has good lubrication performance?Because, the microstructure of WS2 crystal is layered hollow sphere with hexagonal crystalclusters, whose surfaces are formed by hexagonal networks with SWS molecules combinedup, whose layers are connected by Van de Walls Force, this weak binding force is easy to besheared between layers, so the low friction factor is put up. Meanwhile, WS2 crystal is verystable at high temperature, even above 550, WS2 can build up compact WO3 covering layer byslow oxidation to inhibit further oxidation, and WO3 has low friction factor and can prevent theglue happened between metal surfaces as well.

3. Characteristics comparison among Tungsten Disulfide(WS2 ), Molybdenum Disulfide (MoS2 )and Graphite Tungsten Disulfide offers excellent lubrication under extreme conditions of Load,Vacuum and Temperature. The properties below show that Tungsten Disulfide offers excellentthermal stability and oxidation resistance at higher temperatures. WS2 has thermal stabilityadvantage of 93oC (200oF) over MoS2. Coefficient of Friction of WS2 actually reduces at higherloads.

Table 1: WS2 / MoS2 physical and Technical Properties

properties Tungsten disulfide (WS2)

CAS No 12138099

Molybdenum Disulfide (MoS2)

CAS No 1317335

Colour Silver Gray BlueSilver Gray

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Appearance Crystalline Solid Crystalline Solid

Melting Point (oC) 1250oC, 1260oC (decomposes) 1185oC (decomposes)

Boiling Point 450o C

Density (Kg.m3) 7500 5060

Molecular Weight 248 160.08

Coefficient of Friction 0.03 Dynamic; 0.07 Static

Thermal Stability in Air COF



Manmade Solids Manmade Solids

Table 2: comparison of the friction coefficient () and the diameter of scuff scar among threematerials

Item

Load(kg)

graphite MoS2 WS2

frictionfactor

frictionvestige

(mm)

frictionfactor

frictionvestige

(mm)

frictionfactor

frictionvestige

(mm)

21 0.0194 0.241 0.0194 0.268 0.197

25 0.0490 0.255 0.0204 0.270 0.250

31 0.0526 0.312 0.0180 0.283 0.0066 0.266

34 0.0601 0.316 0.0240 0.288 0.0240 0.270

38 0.0269 0.301 0.0296 0.282

40 0.0459 0.312 0.0375 0.309

44 0.0510 0.324 0.0348 0.318

48 0.0511 0.331 0.0375 0.325

52 0.0572 0.349 0.0333 0.343

56 0.0565 0.370 0.0419 0.353

61 0.0452 0.354

66 0.0448 0.361

From the data above we can conclude that basing on fourball extreme pressure test, the itemvalue of the average scuff scar's diameter and the friction factor is ranked as: graphite MoS2



WS2; and PB is WS2 MoS2 graphite, thus we may draw a conclusion that the lubricationperformance is WS2 MoS2 graphite.

4. The application of WS2Tungsten Disulfide (WS2) can be used instead of Molybdenum Disulfide(MoS2)and Graphite in almost all applications, and even more. Molybdenum and Tungsten arefrom same chemical family. Tungsten is heavier and more stable. Molybdenum Disulfide (Alsoknown as Molybdenum Disulfide) till now has been extremely popular due to cheaper price,easier availability and strong and innovative marketing. Tungsten Disulfide is not new chemicaland has been around as long as Molybdenum, and is used extensively by NASA, military,aerospace and automotive industry.Till few years ago, price was Tungsten Disulfide was almost10 times that of Molybdenum Disulfide. But since then price of Molybdenum Disulfide hasdoubled every six months. Now the prices of both chemicals are within comparable range. Now,it makes more economic sense to use superior dry lubricant (Tungsten Disulfide) and improvethe quality and competitiveness of terminal product.

1). WS2 powder worked as additives for lubricants (such as oil, grease & other syntheticlubricants) The powder can be mixed 1% to 15% v/v (as required) with grease or oil. This willenhance lubricity of the mixture and also improves High Temperature and Extreme Pressureproperties of mixture. During the use, WS2 in the mixture will get coated on mating/movingparts, which in turn reduces friction and improves lubricity and load bearing ability for muchlonger cycles.

2). Coating the WS2 powder on a substrate requiring (dry) lubricity The powder can be coatedby spraying at 120 psi (0.8 Mpa) the substrate with dry (& cool) pneumatic air. It does notrequire any binders and spraying can be done at normal room temperature. Coated film will be0.5 micron thick. In an alternative application method, the powder can also be mixed withIsopropyl alcohol and this paste could be buffed to the substrate. The coating applications arealready established in many areas such as Automotive parts, Racing Car Engine and other parts,Aerospace parts, Bearings (Linear, Ball, Roller etc), Shafts, Marine parts, Cutting Tools, Blades,Slitters, Knives, Mold release, Precision Gears, Valve components, Pistons, Chains, Machinerycomponents and many other areas.Besides, it can also be applied to antifriction material incarbon industry; super rigidity material and weld thread;Tungsten Disulfide (WS2) can be usedinstead of Molybdenum Disulfide (MoS2) in almost all applications, and even more. Since thepowder offers one of the lowest Coefficient of Friction (Dynamic at 0.03 & Static at 0.07), theapplications are unlimited and could be tried with every conceivable idea. .

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The following are established ways the WS2 powder can be used

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What is WS2_ - WS2 Oil