Lubricating nanoparticle
Lubricants are needed to minimize the amount of friction and wear generated in machinery. In carrying out this function, lubricants need to be situated on the surfaces of metals and other substrates as interactions between lubricants and metal surfaces occur at the molecular level.
Lubricant nano additives
Development of nanoparticle containing lubricants and lubricant additives involves stabilizing basic lubricant additives as anti wear and extreme pressure (EP) agents in carriers such as mineral oil.
These agents are applied as solid coatings or used in mineral oil-based dispersions. Solid coatings will perform well for a time but tend to be worn away due to the presence of sharp asperities. Inorganic-based nanoparticle oil dispersions are not stable, and the lubricant additive readily precipitates out or agglomerates into larger particles that are ineffective. Development of nanoparticles that can exhibit anti wear and EP performance are with current lubricant base stocks and exhibit even more environmentally friendly characteristics.
Commercial package
NanoMech has integrated layered inorganic solid lubricant nanoparticles of molybdenum disulfide with canola oil to form a solid lubricant exhibits lubricity and EP characteristics and is commercially known as NanoGlide.
The organic-inorganic nanoparticle-based package developed by NanoMech can also be readily incorporated into most conventional base stocks used in the preparation of lubricants. The use of canola oil also means that the organic-inorganic nanoparticle-based additive is environmentally friendly and can provide good sustainability. The organic-inorganic nanoparticle based package can be utilized in automotive lubricants, biodegradable lubricants, gear oils for earth movers and heavy machinery,for infrastructure development, naval ships, etc., and for greases and metalworking fluids.
Nanoscale tungsten
Nanoscale tungsten comprising substances such as tungsten disulfide are useful lubricating additives offering reduced costs at higher performance. Such lubricating nanoparticles offer ability to distribute forces more uniformly due to thinner film formation. The unusual characteristic that makes lubricating nanoparticle additives useful is that the particle size is less than the naturally occurring characteristic roughness sizes and so the nanoparticles can enter and buffer (or reside) in crevices, troughs thereby reducing the damaging internal pressures, forces and inefficient thermal effects. These additives can be dispersed in existing or new lubricating formulations and provide an easy way to incorporate the benefits of nanotechnology. Tungsten disulfide, molybdenum disulfide, molybdenum tungsten sulfide and such inorganic or organic nanoparticle composition are useful lubricating additives.
Carbon nano-onion
The carbon nano-onion can be used as lubricating nanoparticle. When used as lubricant additives, carbon nano-onions lead to a strong reduction of both friction and wear, even at low temperature. The lubrication mechanism of the onions is based on the process of rolling and sliding inside the contact area. Most of carbon onions seem to remain intact under friction processes and do not generate graphitic planes in contrast to the previously reported conventional behavior.
Solid lubricant layer
Japanese researchers formed lubricants with carbon onion layers compounded with gold by dispersing carbon onions on a silicon wafer coated with gold. The carbon onion layer compounded with gold has kept lower-friction coefficient for a longer time than gold layer in a certain range of gold film thicknesses and normal forces. In addition, carbon onion layer on a self-assembled monolayer exhibited the low-friction property under a wide range of normal forces.
Denmark researchers used transition-metal dichalcogenides as solid lubricants. Sputtered coatings and stoichiometric coatings perform optimally made with ion bombardment as a post-coating process. Stoichiometric-powder granulates were dispersed in isopropanol and ball-milled to obtain a nanoplatelet suspension. The coating was deposited by electro spraying.
Titania/diamond nanocomposite
Diamond nanoparticles have excellent lubricating ability. The fabrication of TiO2 based matrix composites with dispersed diamond nanoparticles are synthesized by a detonation method. The mixing process utilizing a sol – gel method achieved a homogeneous mixture between the diamond nanoparticles and the TiO2 gel by ball milling and consolidated at high temperature by spark plasma sintering. The dispersed diamond nanoparticles of 1 vol.-% were chemically stable with improved coefficient of friction and wear rate at high consolidating temperature.
Cu nanoparticles
Cu and Cu alloy nanoparticles have exhibited excellent friction reduction and wear resistance properties. The working of nanoparticles as additives in oil to reduce friction and wear can be considered by two viewpoints; as ball bearing mechanism and film forming mechanism. For the ball bearing mechanism, chemical/mechanical reactions do not occur. Recent studies indicate that local overheating in friction may imitate deposition of copper and forming of a thin protective film on the worn surface to reduce the friction and wear.
The Chinese researchers state that mechanism can be that friction shearing force and high pressure at the interface can initiate the disengagement of Cu nanoparticles from their organic modified layers, and then high temperature due to direct contact of two surfaces originates melting of the bare Cu nanoparticles. In addition, due to good wetting property on steel surface, the liquid copper may well wet the friction pairs. Afterwards, it can be smeared on the worn surface by the shearing movement. Consequently, a copper protective film is formed.