Abstract
Oils and greases are commonly used for lubricating, rotating and sliding systems such as bearings, gears, connectors, etc. The maintenance of such lubricated systems in some applications where access is difficult (e.g., offshore wind farms and subsea equipment) increases the operational costs. In some cases, it can be thought that the use of solid lubricants (MoS2, PTFE, graphite, etc.) embedded in coatings could be a solution for such applications; however, the mechanical and dynamic conditions of most of the systems are not appropriate for solid lubricants. Despite this, solid lubricants such as PTFE and MoS2 have been largely employed in different industries, especially in those applications where liquid lubricants cannot be used and when the dynamic conditions allow for it. Self-lubricated coatings have been a major topic of interest in thermal spray in the last decades. Although the use of liquid lubricants is desirable whenever it is possible, limited research has been addressed toward the development of self-lubricated coatings containing liquid lubricants. One of the main reasons for this is due to the complexity of embedding liquid lubricant reservoirs inside the coating matrix. In the present work, a new type of liquid-solid self-lubricated coatings is presented, being the matrix a metal alloy. Three thermal spray techniques used were as follows: arc-spray, plasma spray, and HVOAF. The metal matrices were two stainless steel types and liquid lubricant-filled capsules with different liquid contents were used. No degradation of the capsules during spraying was observed and the coatings containing capsules were able to keep a low coefficient of friction. The optimal performance is found for the coatings obtained at the lowest spraying temperature and velocity.
Similar content being viewed by others
References
S. Armada, R. Schmid, S. Equey, I. Fagoaga, and N. Espallargas, Liquid-Solid Self-lubricated Coatings, J. Therm. Spray Technol., 2013, 22(1), p 10-17
N. Espallargas, L. Vitoux, and S. Armada, The Wear and Lubrication Performance of Liquid-Solid Self-lubricated Coatings, Surface and Coatings Technology. In Press, Corrected Proof. doi:10.1016/j.surfcoat.2013.07.063
C. DellaCorte and B.U. Edmonds, US Patent 5,866,518, 1999
A. Borisova, Y. Borisov, A. Tunik, L. Adeeva, E. Lugscheider, and C. Herbst, Thermal Spraying of Coatings Containing Solid Lubricants. Proceedings of the United Thermal Spray Conference, 1999, p 174-181
U. Männikkö, A. Määttä, P. Vuoristo, and T. Mäntylä, Preparation of Powders and HVOF Sprayed Coatings for Improved Sliding Properties by Addition of Solid Lubricants. Proceedings of the International Thermal Spray Conference, 2002, p 676-680
Maintenance and OSH—A statistical picture. Report from the European Agency for Saftety and Health at Work. http://osha.europa.eu/en/publications/factsheets/90
S.R. White, N.R. Sottos, P.H. Geubelle, J.S. Moore, M.R. Kessler, S.R. Sriram, E.N. Brown, and S. Viswanathan, Autonomic Healing of Polymer Composites, Nature, 2001, 409, p 794-797
R.P. Wool, Self Healing Materials: A Review, Soft Matter, 2008, 4, p 400-418
M.R. Kessler, Self-healing: A New Paradigm in Materials Design, Proc. Inst. Mech. Eng. G, 2007, 221(4), p 479-495
P. Patel, A Metal Coating That Repairs Itself, MIT Technology Review, News and Analysis, August 10, 2009
N. Espallargas and S. Armada, Self-lubricated Coatings Obtained by Thermal Spray Methods, Patent number WO 2013/058660
H. Johnsen and R.B. Schmid, Preparation of Polyurethane Nanocapsules by Miniemulsion Polyaddition, J. Microencapsul., 2007, 24(8), p 731-742
G.W. Stachowiak and A.W. Batchelor, Engineering Tribology, 3rd ed., Butterworth-Heinemann, Dordrecht, 2006, ISBN 978-0-7506-7836-0
L. Pawlowski, The Science and Engineering of Thermal Spray Coatings, Wiley, Chichester, 1995 (414 pp)ISBN 0-47-159253-2
W.D. Callister, Materials Science and Engineering, SI Version, 8th ed., Wiley, New York, 2010
F. Cardarelli, Materials Handbook, 2nd ed., Springer, London, 2005
Acknowledgements
The authors would like to acknowledge R. Schmid and H. Johnsen (SINTEF Materials and Chemistry) for producing the capsules through the internal project LiSoCo. The authors would also like to thank C. Vaquero, I. Fagoaga and G. Barykin (Tecnalia, Spain) and C. Torres (NTNU, Norway) for the help in the coatings’ production and testing.
Author information
Authors and Affiliations
Corresponding author
Additional information
This article is an invited paper selected from presentations at the 2014 International Thermal Spray Conference, held May 21-23, 2014, in Barcelona, Spain, and has been expanded from the original presentation.
Rights and permissions
About this article
Cite this article
Espallargas, N., Armada, S. A New Type of Self-lubricated Thermal Spray Coatings: Liquid Lubricants Embedded in a Metal Matrix. J Therm Spray Tech 24, 222–234 (2015). https://doi.org/10.1007/s11666-014-0152-8
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11666-014-0152-8