Publication detail

Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions

POLÁČEK, T. ŠPERKA, P. KŘUPKA, I.

English title

Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions

Type

journal article in Web of Science

Language

en

Original abstract

Macroscale rolling/sliding conditions are in the superlubricity, a little-studied topic so far. The purpose of this paper is to examine the formation of elastohydrodynamic lubrication (EHL) films by water-based lubricants (glycerol and polyethylene glycol (PEG)), providing superlubricous friction. Experiments were carried out on an optical ball-on-disc tribometer under rolling/sliding conditions. The film thickness was measured by the thin film colorimetric interferometry, and the viscosity of liquids was measured by rotational and high-pressure falling body viscometers. The results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based lubricants. The studied liquids themselves are almost Newtonian. With the addition of water, the signs of shear thinning behavior disappear even more. Suitable conditions for this type of lubricant can be predicted using the known Hamrock-Dowson equations. An anomaly in the thickness of the lubricants was observed as an abrupt change at certain conditions. The more PEG there is in the lubricant, the higher the thickness at the beginning of the jump.

English abstract

Macroscale rolling/sliding conditions are in the superlubricity, a little-studied topic so far. The purpose of this paper is to examine the formation of elastohydrodynamic lubrication (EHL) films by water-based lubricants (glycerol and polyethylene glycol (PEG)), providing superlubricous friction. Experiments were carried out on an optical ball-on-disc tribometer under rolling/sliding conditions. The film thickness was measured by the thin film colorimetric interferometry, and the viscosity of liquids was measured by rotational and high-pressure falling body viscometers. The results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based lubricants. The studied liquids themselves are almost Newtonian. With the addition of water, the signs of shear thinning behavior disappear even more. Suitable conditions for this type of lubricant can be predicted using the known Hamrock-Dowson equations. An anomaly in the thickness of the lubricants was observed as an abrupt change at certain conditions. The more PEG there is in the lubricant, the higher the thickness at the beginning of the jump.

Keywords in English

macroscale superlubricity; super low traction; water-based lubricants; elastohydrodynamic lubrication (EHL); film thickness

Released

28.07.2023

Publisher

TSINGHUA UNIV PRESS

Location

BEIJING

ISSN

2223-7704

Volume

12

Number

1

Pages from–to

164–173

Pages count

10

BIBTEX


@article{BUT185046,
  author="Tomáš {Poláček} and Petr {Šperka} and Ivan {Křupka},
  title="Liquid superlubricity of lubricants containing hydroxyl groups and their aqueous solution under rolling/sliding conditions",
  year="2023",
  volume="12",
  number="1",
  month="July",
  pages="164--173",
  publisher="TSINGHUA UNIV PRESS",
  address="BEIJING",
  issn="2223-7704"
}