Utilization of nanodiamonds canimprove the efficiency of engines by adding it into lubricants which decreases thefuel consumption by ~5%. It is presume that this take hold the effect dueto the presence of graphite in the soot which is responsible for lubricationand frictional coefficient was reduced due to polishing roughnessdecreses on sliding surfaces by nanodiamonds110. Even though, itis noticed that the purified nanodiamonds spread alone or withpolytetrafluoroethylene (PTFE) or metal nanoparticles in greases or oils whichcan improve the tribiological performances.
In fact, it was considered that thenanodiamonds acted as ‘ball bearings’, but this has not been established asuniversal in new studies, which willshow that various lubrication mechanisms could be at work in diversesystems. For example, lodging nanodiamond from a lubricant to a carbonsteel surface may reveal decreased friction and wear, whereas the wearmechanism for an aluminium alloy is influenced by the viscosity of thenanodiamond suspension. The versatile surface chemistry ofnanodiamond means that it can be modified so thatit disperses in a variety of diverse systems,comprising oil and water. Carbon onions can also operateas an efficient lubricant, possibly owing tothe microscopic ball-bearing action.
Overall, lubricationis more complex than it looks at early, but it is reasonable topresume that both nanodiamonds and carbon onions inserted into metal surfaces dividethe sliding surfaces and prevent wear generated bymetal-metal adhesion111,112. Nanodiamonds synthesized under highlynonequilibrium conditions have no different crystalline faceting; their roundshape and high affinity for a carbon base of oils and lubricants, strengthenedby surface modification, provides their efficient application as constituentsof liquid, consistent, and solid lubricants. The introduction of isometricnanodiamond particles and graphite–diamond mix up to 10 nm in size intolubricants which makes it feasable to change the mechanism of the contactinteractions of a friction pair, to increase the surface layer microhardness,and to inhibit metal-metal contact at thefriction surface. The self-accommodation time is exceptionally reduced, afterwhich the wear intensity sharply decreases (by a factor of 2–4). The frictionsurface take hold of a characteristic high lustrethat is originate by an considerable decrease in roughness, and the frictioncoefficient reduce by 15–20%90,113.
Diamondand diamond–carbon clusters expend the lubricant viscosity in thin films, andtheir dynamic strength and resilience expand considerabally, which in turn minimize the leakages throughclearances and gaskets in internal-combustion engines (ICEs) and reduce frictionloss, thereby increase the compression and service life of carburettor anddiesel ICEs and fuel economy. Nanodiamond suppliment in solid lubricants permitno-wear operation of sliding bearings of vapourboilers and turbine units in the power-supply system in Belarus114,115. The great potential of a new anti-frictionheterogeneous material composed of Sn–Zn–Pb bronze and cast iron granules that wasapplied in application using a special stable lubricant with a nanodiamondadditive. Only the application of the stable lubricant enhance by the nanodiamondsprovided no-wear operation of journal bearings, the non appearence of seizure,and dimnish in the friction coefficient paired with steel from f =0.12–0.18 to0.
08 -0.10 at specific loads up to 300 MPa39. Moderationupgrade the mechanical properties and in various cases, give unique tribal-technical properties due to the developmentof a space network of physical bonds at the interface between the polymer matrixand nanoparticles having enhanced adsorption characteristics116.Atechnology for gas-flame deposition of single andmultilayer polymer coatings with dispersed nanodiamonds has beendeveloped117. In thecase of single-layer sputtering, the deposited material is a mechanical mixtureof a polyamide powder with ultrafine-dispersed diamonds and also with metal andceramic components. The developedtechnology makes it possible to deposit coatings of various thicknesses ontofriction units with various shapes and sizes. Two-layer metal–polymer coatingswith 0.
5 wt % ultrafine-dispersed diamonds formed by gas-flame depositionreliably protect bearings and rotors of immersed pumps and other units againstthe joint influence of corrosion and wear, which makes it possible to keep goodoperating properties over a long period of time. Ultrafine dispersed diamondsincrease the density, coating–substrate cohesion and lubricant adhesion to thefriction surface, which increases the service life by a factor of 1.5–2.Polymer coatings enhanced by nanodiamonds are characterized by goodantifriction properties, mechanical strength, non-toxicity, noiselessness, goodmachinability by cutting tools as well as high resistance to liquid fuel,mineral oils and fats, organic solvents, alkali, and acids118,119.