Additives for improving motor oil properties

#The invention relates to an oil composition, particularly a lubricating oil composition for use in a submersible electric motor.

#Oils are used for a variety of applications, including providing lubrication for engines and motors to extend lifetime and prevent failure. Oils that are used as lubricants provide lubrication between two moving surfaces, such as for example, bearings and other metal surfaces, to improve motor efficiency and improve motor run life. Additionally, lubricants are useful for carrying away heat that is generated within the motor, thereby reducing the operating temperature. Finally, oil may function as an electrical resistor between the stator and rotor in a motor.

#Oils are generally selected based upon a desired viscosity at a specified operating temperature. Preferably, oils are selected to ensure efficient operation of a motor or engine at desired operating temperatures by providing sufficient viscosity to provide lubrication, while at the same time having sufficient lubrication to minimize friction. Additionally, oils preferably have good thermal conductivity to ensure they efficiently carry away heat generated by the operation of the motor. Finally, it is preferable that the oil have a high electrical resistance.

#Although the following detailed description contains many specific details for purposes of illustration, it is understood that one of ordinary skill in the art will appreciate that many examples, variations and alterations to the following details are within the scope and spirit of the invention. Accordingly, the exemplary embodiments of the invention described herein are set forth without any loss of generality to, and without imposing limitations thereon, the claimed invention.

#In one aspect of the present invention, a lubricant composition having improved thermal, electrical and tribological properties is provided. Generally, the lubricant composition includes a base oil and at least one nanoparticle additive suspended therein. Suitable oils for the base oil are hydrocarbon based and may be natural oils or synthetic oils. As used herein, natural oil refers to a naturally occurring liquid consisting of a mixture of hydrocarbons having various molecular weights, which has been recovered from a subsurface rock formation, and may have been subjected to a refining process. As used herein, synthetic oil refers to a hydrocarbon liquid that consists of chemical compounds not originally present in crude oil, but were instead artificially synthesized from other compounds. As used herein, nanoparticles refers to particles or agglomerates having an average mean diameter of less than about 250 nm, preferably less than 200 nm, and more preferably between 5 and 150 nm.

#Exemplary nanoparticle additives can include, but are not limited to, carbon nanotubes; carbon nano-onions; graphite nanoparticles, nanotubes or nanofluids; diamond nanoparticles or nanofluids; silicon dioxide nanoparticles or organic functionalized derivatives thereof; aluminum oxide nanoparticles or organic functionalized derivatives thereof; metal oxide nanoparticles (such as, for example, magnesium oxide, calcium oxide or copper oxide); metal sulfonates nanoparticles (such as, for example, magnesium sulfonate or calcium sulfonate); tungsten disulfide nanoparticles or nanotubes; molybdenum disulfide nanoparticles or nanotubes; alumoxane nanoparticles or functionalized derivatives thereof (such as, for example, carboxylate-alumoxane); beryllium oxide nanoparticles and nanotubes; carbide nanoparticles (such as, for example, silicon carbide, tungsten carbide or boron carbide); and nitrides (such as, for example, aluminum nitride); and combinations thereof. Preferably, the nanoparticle additive is at least slightly soluble in the lubricant composition. Exemplary shapes of the individual nanoparticles can include single or multi-walled nanotubes, spheres/balls, ribbons, and donut/wheel shapes. The particles can have a long dimension of up to about 250 nm in diameter or length, preferably up to about 200 nm in diameter or length.