Spherical Tungsten Disulfide Dispersed by Ionic Liquid

Cations in ionic liquid form a cation layer around spherical tungsten disulfide particles to prevent their contact. In this way, ionic liquid can effectively disperse spherical tungsten disulfide in lubricating oil.

tungsten disulfide particle image

Spherical tungsten disulfide particle has a small size and a large specific surface area, together with a high specific surface energy and surface activity. So it is prone to agglomeration in lubricating oil. The agglomeration of particles means that they polymerize each other due to interaction force in gas or liquid phase. As the solvent of lubricating oil, ionic liquid can effectively disperse the spherical tungsten disulfide in lubricating oil, so that the tungsten disulfide particles can move freely with each other.

Ionic liquid is an efficient green solvent, which has been widely used in electrochemistry, catalysis, organic synthesis and other fields. Ionic liquid is a salt composed of two parts, the anion and the cation, which is liquid below 100°C. Due to the strong internal force of ionic liquid, ionic liquid can be firmly adsorbed on most solid surfaces, thus forming a lubricating boundary layer.

mechanism of ionic liquid on spherical tungsten disulfide image

In addition, ionic liquid is non-flammable and non-explosive, with low melting point, good solubility and high thermal stability. Therefore it is considered as a promising new lubricant. Currently, ionic liquid is commonly used as a lubricating solvent. It is generally composed of cations belonging to organic substances and anions belonging to inorganic substances.

In lubricating oils containing spherical tungsten disulfide, cations of the ionic liquid form a cationic layer around the spherical particles. This process can effectively prevent the contact and agglomeration between tungsten disulfide particles, so that the spherical tungsten disulfide can be stable and dispersed for a long time in the lubricating oil. Furthermore, the lubricating oil containing spherical tungsten disulfide can show a good lubricating performance in the processing of machines.