Phosphonium-based ionic liquids as additives in calcium/lithium greases

Authors: García Tuero, A., Bartolomé, M., Gonçalves, D., Viesca, J.L., Fernández-González, A., Seabra, J.H.O. and Hernández Battez, A.

Journal: Journal of Molecular Liquids

Volume: 338

ISSN: 0167-7322

DOI: 10.1016/j.molliq.2021.116697

Abstract:

This work studies the performance of three phosphonium-based ionic liquids ([P6,6,6,14][BEHP], [P6,6,6,14][TCM] and [P6,6,6,14][DEC]) when used separately as additives on the thermal conductivity, thermal stability and tribological properties of two non-additised greases (a lithium-based and a calcium-based grease). The main results confirmed that the [P6,6,6,14][TCM] improved the thermal stability of both greases. Only the mixtures G1 + 5%[P6,6,6,14][BEHP] and G2 + 5%[P6,6,6,14][TCM] showed a slight increase in thermal conductivity. In general, the addition of the ILs to the lithium-based grease increased the friction coefficient in both the four-ball tests and the reciprocating tests, while the friction coefficient decreased with the addition of the ILs to the calcium-based grease in the four-ball tests. The addition of the [P6,6,6,14][BEHP] and [P6,6,6,14][TCM] improved the antiwear behavior of the lithium-based grease under both tribological tests, whereas all the ionic liquids worsened the antiwear behavior of the calcium-based grease in the four-ball tests. The [P6,6,6,14][BEHP] had the best antiwear behavior due to the higher interaction of phosphorous with the metal surface. A possible interference of the calcium thickener with the ionic liquid–metal surface interaction was found, resulting in lower antiwear behavior of the mixtures with the calcium-based grease.

https://eprints.bournemouth.ac.uk/35693/

Source: Scopus

Phosphonium-based ionic liquids as additives in calcium/lithium greases

Authors: Garcia Tuero, A., Bartolome, M., Goncalves, D., Viesca, J.L., Fernandez-Gonzalez, A., Seabra, J.H.O. and Hernandez Battez, A.

Journal: JOURNAL OF MOLECULAR LIQUIDS

Volume: 338

eISSN: 1873-3166

ISSN: 0167-7322

DOI: 10.1016/j.molliq.2021.116697

https://eprints.bournemouth.ac.uk/35693/

Source: Web of Science (Lite)

Phosphonium-based ionic liquids as additives in calcium/lithium greases

Authors: García Tuero, A., Bartolomé, M., Gonçalves, D., Viesca, J.L., Fernandez-Gonzalez, A., Seabra, J.H.O. and Hernandez Battez, A.

Journal: Journal of Molecular Liquids

Volume: 338

Issue: September

ISSN: 0167-7322

Abstract:

This work studies the performance of three phosphonium-based ionic liquids ([P6,6,6,14][BEHP], [P6,6,6,14][TCM] and [P6,6,6,14][DEC]) when used separately as additives on the thermal conductivity, thermal stability and tribological properties of two non-additised greases (a lithium-based and a calcium-based grease). The main results confirmed that the [P6,6,6,14][TCM] improved the thermal stability of both greases. Only the mixtures G1 + 5%[P6,6,6,14][BEHP] and G2 + 5%[P6,6,6,14][TCM] showed a slight increase in thermal conductivity. In general, the addition of the ILs to the lithium-based grease increased the friction coefficient in both the four-ball tests and the reciprocating tests, while the friction coefficient decreased with the addition of the ILs to the calcium-based grease in the four-ball tests. The addition of the [P6,6,6,14][BEHP] and [P6,6,6,14][TCM] improved the antiwear behavior of the lithium-based grease under both tribological tests, whereas all the ionic liquids worsened the antiwear behavior of the calcium-based grease in the four-ball tests. The [P6,6,6,14][BEHP] had the best antiwear behavior due to the higher interaction of phosphorous with the metal surface. A possible interference of the calcium thickener with the ionic liquid–metal surface interaction was found, resulting in lower antiwear behavior of the mixtures with the calcium-based grease.

https://eprints.bournemouth.ac.uk/35693/

Source: BURO EPrints