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Ionic Liquids as Lubricants or Additives

Oak Ridge National Laboratory

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Technology Marketing SummaryNew ionic liquids invented at ORNL show great promise as lubricants for aluminum and steel in combustion engines, bearings, and microelectromechanical systems (MEMS). The ammonium-based ionic liquids are strongly adsorbant on contact surfaces, leading to a more than 30% friction reduction in metal-based interacting parts, compared with conventional 15W40 engine oil. This new class of lubricants can lead to dramatic energy savings: Friction and wear in machine parts costs the United States around $700 billion annually. DescriptionIonic liquids offer several other advantages. They have negligible volatility, high thermal stability, are nonflammable, and have intrinsic properties that eliminate the need for expensive lubricant additives. Room temperature ionic liquids are familiarly known as “green solvents,” and this invention broadens the set of applications as researchers show that ionic liquids/ammonium cations are potential lubricants or additives.

ORNL researchers prepare ionic liquids from ammonium salts of primary, secondary, and tertiary amines. The salts display good viscosities for lubricating surfaces at high and low temperatures, good thermal stability compared with mineral oil and conventional motor oils, and a low affinity for water. They have low melting points, generally below 25°C. While no wear reduction was observed with 100% ionic liquids, a mixture of mineral oil and 10% ionic liquid by volume resulted in lower wear than either a base oil or the 100% ionic liquid. This suggests a great potential for using them as lubricant additives.
  • Cost savings due to reduced friction and wear of mechanical parts
  • Better friction reduction than conventional hydrocarbon oils
Applications and Industries
  • Combustion engines and bearings
  • MEMS
  • Metal forming
More InformationLead Inventor:
Jun Qu
Materials Science and Technology Division
Oak Ridge National Laboratory
Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 7,754,664
Lubricants or lubricant additives composed of ionic liquids containing ammonium cations
A lubricant or lubricant additive is an ionic liquid alkylammonium salt. The alkylammonium salt has the structure R.sub.xNH.sub.(4-x).sup.+,[F.sub.3C(CF.sub.2).sub.yS(O).sub.2].sub.2N.sup- .- where x is 1 to 3, R is independently C.sub.1 to C.sub.12 straight chain alkyl, branched chain alkyl, cycloalkyl, alkyl substituted cycloalkyl, cycloalkyl substituted alkyl, or, optionally, when x is greater than 1, two R groups comprise a cyclic structure including the nitrogen atom and 4 to 12 carbon atoms, and y is independently 0 to 11. The lubricant is effective for the lubrication of many surfaces including aluminum and ceramics surfaces.
Oak Ridge National Laboratory 07/13/2010
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated
UT-B ID 200501661DevelopmentAvailable10/20/201012/08/2010

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To: Jennifer Tonzello Caldwell<>