Improved Production of molybdenum sulfide Nanoparticles offered by IMG
IMG Innovations-Management GmbH
Ground crystalline molybdenum sulfide (MoS2) has reliably proven itself as a universal and inert solid lubricant. Its lubricity could lately be outperformed by nano-MoS2 which fills smaller surface roughnesses and exerts lower inter-particle shear resistance. But since it represents a metastable modification, its synthesis is intricate and often results in low yields only. According to the only hitherto industrially feasible method nano-MoS2 is obtained from MoO3 powder in concurrent sublimation, reduction, and sulfidation operations. In order to mechanically maintain particle fine dispersions throughout the process and to synchronise all individual reaction steps chemical reactors of high engineering complexity are required.
Through a crucial modification of this fundamental process the synthesis of nano-MoS2 in a two-stepreaction starting from ammonium heptamolybdate now succeeded. Kinetic complexity is reduced through technological separation of the nucleation and growth of oxide nanocrystallites from their subsequent sulfidation. The first thermolysis step already goes along with the formation of sub-oxides which appear to promote the following conversion such that it can be carried out without additional reducing agents. The overall process results in amixture of multi-walled, hollow inorganic fullerene (IF) and nanotube (NT) particles of which softer elasticities are expected compared to previously known materials containing residual oxidic cores.
Preparation of MoS2 or WS2 nanoparticles for uses in special-purpose lubrication (at high temperatures or loads, vacuum or cleanroom conditions) and also as potential hydrodesulfurisation catalysts.
- Fast and high-yield conversion at moderate temperatures
- Easily up-scalable using standard equipment; low investment costs only
- Uses inexpensive, commercial-grade starting material; no extra purification steps
- Robust and insensitive towards a wide range of temperature and flow conditions; no precise parameter control necessary
- Compatible with various sulfurising agents; added safety: supersedes hydrogen gas mixtures
- Proportions of IF and NT particles controllable via temperature and reaction time; product mixture shows superior lubricity
Stage of Development
- Mechanistic studies of the conversion process and its intermediates; optimisation of reactant mixture, apparatus design and process parameters
- Morphological characterisation of final products by electron microscopy, diffraction techniques,and EDX analysis; tribological data available
German patent granted and European patent pending.
Licence or sales agreement covering manufactureand distribution.