Mo-Carbonyl Phosphate (Item No. T300) is a blue-gray-black, lustrous fine powder with a greasy feel, supplied in two grades (T300A and T300B) and optionally in nano-grade. It is positioned as a solid lubricating material and extreme-pressure (EP) additive, offered as a replacement for molybdenum disulfide in a range of tribological applications. This article summarizes its characteristics, specification envelope, and the engineering rationale behind its use.
1. Physical and Chemical Characteristics
| Property | Value |
| Appearance | Blue-gray-black lustrous fine powder, greasy feel |
| Mohs hardness | 0.8–1.3 |
| Friction coefficient | 0.05–0.1 |
| Oil absorption value | 2.6–4.0 |
| Melting point | 850 °C |
The material does not sublime and shows good chemical and thermal stability. In air it begins to gradually oxidize above 600 °C. It is insoluble in — and does not react with — dilute acids, alkalis, solvents, lubricating oils, or synthetic greases. These properties are the basis for its use in high-temperature and chemically aggressive environments where conventional organic lubricants degrade.
2. Lubrication Mechanism
The functional behavior of Mo-Carbonyl Phosphate is twofold. First, it readily disperses on the surface of oil molecules, supporting stable suspension in grease and oil formulations. Second, on contact with metal surfaces it undergoes **internal phosphating**, forming two distinct films: an **anti-wear layer** and a **surface adhesion layer**. These films are resistant to extreme pressure and friction, have no adverse effect on the metal substrate, and do not corrode rubber materials — a relevant point for seal and hose compatibility in grease-lubricated systems.
3. Specification Envelope
| Item | T300A | T300B |
| Appearance | Blue-gray-black lustrous fine powder
| MoO (%) | ≥30 | ≥16 |
| Carbon content (%) | ≤60 | ≤69 |
| P₂O₅ (%) | ≥8 | ≥11 |
| Moisture content (%) | ≤1.0 | ≤1.0 |
| 325-mesh sieve residue (%) | ≤0.5 | ≤0.5 |
| Corrosion (100 °C, 24 h), grade | ≤2 | ≤2 |
| Maximum non-seizure load P_B (four-ball), N | ≥100 kg | ≥100 kg |
The two grades trade molybdenum oxide content against phosphorus pentoxide and carbon content. T300A, with higher MoO and lower carbon, suits formulations where the molybdenum-bearing phase is the primary functional component. T300B, with higher P₂O₅ and carbon, offers a higher phosphating potential per unit mass and may be preferred where the surface-film formation is the dominant requirement. Both grades meet the same corrosion and four-ball P_B thresholds, so grade selection is driven by formulation economics and the balance between Mo- and P-mediated mechanisms rather than by load-carrying capability.
4. Application Notes
- Grease additive. The recommended dosage is 2–3 wt%, added directly to the finished grease and stirred to homogeneity. It functions as an anti-wear, EP, anti-oxidation, anti-acid, and anti-chemical-corrosion additive. It is compatible with lithium-based EP greases, complex lithium and complex calcium greases, synthetic greases, and non-soap-based greases.
- Direct solid lubrication.The powder can be brushed onto friction surfaces or introduced into the contact during service. It is intended for lubrication at 600–1000 °C and for high-temperature service in chemically corrosive environments.
- Self-lubricating components.The powder can be compounded with resin and injection-molded into resin bearings, or mixed with metal powders and cast into metal self-lubricating bearings.
- Release agent. It serves as a release agent in injection molding of metals, non-ferrous metals, rubber, and plastics.
- Brake pads and electrical components. It polymerizes readily with resin, improving wear resistance and service life in brake pads; it is also used in carbon brushes and similar electrical parts.
5. Handling and Storage
Supplied in plywood drums at 25 kg net. The material is non-combustible and non-corrosive. It must not be stored or transported with acids. Keep dry, ventilated, and protected from moisture and rain.
6. Selection and Formulation Guidance
For formulators, three practical points follow from the data. The low Mohs hardness (0.8–1.3) and low friction coefficient (0.05–0.1) make the material attractive where abrasive wear of counterfaces is a concern. The 325-mesh residue limit of ≤0.5% bounds coarse-particle content but does not specify a full particle-size distribution, so dispersion behavior in a given grease should be validated empirically; nano-grade is available where finer dispersion is required. Finally, the 600 °C oxidation onset defines the upper bound for air atmospheres — above this temperature, inert or reducing conditions should be considered, and the 600–1000 °C direct-lubrication claim should be read in that light.
