Molybdenum disulfide — commonly written as MoS2 — is one of the most effective solid lubricants known to materials science. Used in aerospace, defense, automotive, and industrial applications for over 70 years, MoS2 continues to be a critical performance additive for lubricant formulators, grease manufacturers, and coating producers worldwide.
What Is MoS2?
Molybdenum disulfide (MoS2) is an inorganic compound consisting of one molybdenum atom bonded to two sulfur atoms in a layered hexagonal crystal structure. It occurs naturally as the mineral molybdenite, but the MoS2 used in lubricants is synthetically refined to precise particle sizes and purities.
Chemical formula: MoS₂ | CAS: 1317-33-5 | Color: Dark gray/black | Crystal structure: Hexagonal layered
Why Is MoS2 an Excellent Solid Lubricant?
MoS2’s lubricating ability comes from its layered crystal structure. Within each layer, Mo and S atoms are strongly bonded. Between layers, only weak van der Waals forces hold the structure together — meaning the layers slide easily under shear stress. This gives MoS2 outstanding properties:
- Coefficient of friction: 0.03–0.15
- Effective from −185°C to +350°C in air; up to 1,100°C in vacuum
- Excellent extreme pressure (EP) performance
- Works in vacuum where oils fail — used in spacecraft
MoS2 in Lubricants, Greases, and Coatings
In lubricating oils: MoS2 dispersions improve anti-wear and EP performance. Surface-modified MoS2 from Powderful Solutions stays stable in oil without settling.
In greases: Typical treat rate 1–5% by weight. Improves anti-wear (ASTM D2266), EP rating (4-ball weld point), and film strength under shock loading.
In dry film coatings: Applied to metal surfaces for long-lasting lubrication. Used on fasteners, aerospace structures, gun mechanisms, molds, piston skirts, and tooling.
MoS2 vs Other Solid Lubricants
| MoS2 | WS2 | hBN | Graphite | |
|---|---|---|---|---|
| Friction coefficient | 0.03–0.15 | 0.03–0.12 | 0.10–0.30 | 0.10–0.20 |
| Max temp (air) | 350°C | 450°C | 900°C | 500°C |
| Vacuum performance | Excellent | Excellent | Good | Poor |
| EP performance | Excellent | Excellent | Moderate | Moderate |
| PTFE-free | ✅ | ✅ | ✅ | ✅ |
FAQ
Q: What is MoS2 used for in lubricants?
A: MoS2 is used as a solid lubricant additive in greases, oils, and dry film coatings. It reduces friction and wear, improves extreme-pressure performance, and lubricates where liquid lubricants fail — high temperatures, vacuum, shock-loaded contacts.
Q: What particle size of MoS2 is best for lubricant formulations?
A: For grease and oil: 0.5–5 micron. For dry film coatings: sub-micron (0.1–0.5 µm) for smoother films. Powderful Solutions offers multiple grades.
Q: Is MoS2 PTFE-free?
A: Yes. MoS2 contains no fluorinated compounds and is a fully PTFE-free, PFAS-free solid lubricant.
Q: Where can I buy surface-modified MoS2?
A: Powderful Solutions supplies surface-modified MoS2 powders and stable oil dispersions. TDS and samples on request. Also see desilubeinc.com for food-grade and PFAS-free formulation guidance.
Powderful Solutions is a US supplier of MoS2, WS2, and hBN solid lubricant powders and dispersions for lubricants, greases, and coatings — powderfulsolutions.com