Tribocatalysis: An overview

Catalysis

A catalyst is a substance that speeds up a chemical reaction, but is not consumed by the reaction; hence a catalyst can be recovered chemically unchanged at the end of the reaction it has been used to speed up, or catalyze. Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst. With a catalyst, the energy required to go into the transition state decreases, thereby decreasing the energy required to initiate the reaction process. [3]

Tribocatalysis

Tribocatalysis is a subsection of tribochemistry dealing with the changes of catalytic properties of solids due to the effect of mechanical energy (mainly friction). [1][2]

Examples of tribocatalytic reactions – Oxidation of carbon monoxide

When palladium is rubbed against aluminum oxide in an atmosphere of carbon monoxide and oxygen, carbon dioxide is produced. When sliding starts, the pressure of carbon monoxide and oxygen decreases whereas pressure of carbon dioxide increases. Hence it can be stated that rubbing of palladium catalyst against aluminium oxide enhances the synthesis reaction of carbon dioxide.[1][2]

Tribocatalysis provides an alternative approach for forming lubricants lubricants with conventional EP additives

A new approach to extreme pressure lubrication has been developed through the use of tribocatalysis. Under severe operating conditions, a nanocoating containing a catalyst based on a transition metal facilitates the in-situ conversion of a lubricant base oil to form a tribofilm containing amorphous carbon species. The tribofilm demonstrates superior reductions in coefficient of friction and wear. [4]

References:

  1. Kajdas, C., and K. Hiratsuka. “Tribochemistry, Tribocatalysis, and the Negative-ion-radical Action Mechanism.” Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 223.6 (2009): 827-48. – Main source of above article
  2. Pawlak, Z. “Chapter 5: Surface Tribochemistry and Activated Processes.” Tribochemistry of Lubricating Oils. Amsterdam: Elsevier, 2003. 183-84
  3. “Definition of Catalyst.” Chemistry Dictionary. Web. 23 Jan. 2017. http://www.chemicool.com/definition/catalyst.html
  4. Tribocatalysis: A new extreme pressure lubrication approach. Dr. Neil Canter (Contributing editor), TLT Magazine – An STLE Publication, October 2016

HARSHVARDHAN SINGH
About HARSHVARDHAN SINGH 17 Articles
Harshvardhan Singh is an Automotive Engineer and has good experience in lubrication science and experimental tribology. He loves to write about tribology and related fields such as coating technology, surface engineering and others.

4 Comments

  1. “A new approach to extreme pressure lubrication has been developed through the use of tribocatalysis. Under severe operating conditions, a nanocoating containing a catalyst based on a transition metal facilitates the in-situ conversion of a lubricant base oil to form a tribofilm containing amorphous carbon species. The tribofilm demonstrates superior reductions in coefficient of friction and wear.”

    Harsh, are you not referring to the process discussed in the Argonne paper reviewed earlier in my story on Argonne embracing “in-operando” (a/k/a in-situ) formation of amorphous carbon tribofilms from catalyst-coated engine parts?

    • Yes, you are right !! 1) Carbon-based tribofilms from lubricating oils; Ali Erdemir,Giovanni Ramirez,Osman L. Eryilmaz,Badri Narayanan, Yifeng Liao,Ganesh Kamath & Subramanian K. R. S. Sankaranarayanan 2) Superlubricity: Seen at the macroscale for the first time:Canter.N. (2015)
      Theses are the other two references. My article is more of about tribocatalysis: General view

  2. Wear particles also act as catalysts for grease and oil oxidation and limit the lifetime of things. It would be interesting to know more about the tribochemistry of this process.

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