Friction Properties of Slippery Liquid-Infused Porous Surfaces
Ajmal, Nawal (2026)
2026
Master's Programme in Materials Science and Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
This publication is copyrighted. You may download, display and print it for Your own personal use. Commercial use is prohibited.
Hyväksymispäivämäärä
2026-07-30
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202607298614
https://urn.fi/URN:NBN:fi:tuni-202607298614
Tiivistelmä
In this work, the friction performance of stainless-steel and alumina slippery liquid-infused porous surfaces (SLIPS) prepared by thermal spraying was studied. The aim was to study the effect of silicone oil infusion on the friction performance of thermally sprayed stainless-steel and alumina porous coatings.
First, porous stainless-steel and alumina coatings were fabricated on low-carbon steel substrates. The stainless-steel coating was produced by arc spraying, while the alumina coating was produced by flame spraying. After coating production, the samples were infused with silicone oil to form SLIPS. Ball-on-disc testing was then performed to compare the coefficient of friction of the SLIPS with as-sprayed non-lubricated coatings.
Coating characterization was carried out to study the coating structure, including coating thickness, porosity, pore size distribution, and surface features after testing. The alumina coating showed an average overall area-fraction porosity of 12.2 %, while the stainless-steel coating showed an average overall area-fraction porosity of 3.1 %. These results showed that the alumina coating had a more porous structure than the stainless-steel coating. The porous structures were then infused with silicone oil to form SLIPS and to study the effect of lubricant infusion on friction behaviour.
A reduction in the coefficient of friction was obtained for both alumina and stainless-steel SLIPS during friction testing. The average COF values were compared at a sliding distance of 80 m. For alumina, the COF decreased from 0.75 for the non-lubricated coating to 0.19 for the alumina SLIPS. For stainless steel, the non-lubricated coating showed a COF value of 0.85. The stainless-steel SLIPS tests showed two different COF curve trends, so the results were divided into two groups for easier comparison. In the first group, the COF decreased to 0.20, while in the second group, it decreased to 0.41. Although some variation was observed between the stainless-steel SLIPS groups, both groups showed lower COF values than the non-lubricated stainless-steel coating. Overall, the SLIPS produced in this work showed clear potential for reducing the coefficient of friction under sliding contact. Therefore, thermally sprayed SLIPS can be considered a promising surface engineering approach for friction reduction in tribological applications.
First, porous stainless-steel and alumina coatings were fabricated on low-carbon steel substrates. The stainless-steel coating was produced by arc spraying, while the alumina coating was produced by flame spraying. After coating production, the samples were infused with silicone oil to form SLIPS. Ball-on-disc testing was then performed to compare the coefficient of friction of the SLIPS with as-sprayed non-lubricated coatings.
Coating characterization was carried out to study the coating structure, including coating thickness, porosity, pore size distribution, and surface features after testing. The alumina coating showed an average overall area-fraction porosity of 12.2 %, while the stainless-steel coating showed an average overall area-fraction porosity of 3.1 %. These results showed that the alumina coating had a more porous structure than the stainless-steel coating. The porous structures were then infused with silicone oil to form SLIPS and to study the effect of lubricant infusion on friction behaviour.
A reduction in the coefficient of friction was obtained for both alumina and stainless-steel SLIPS during friction testing. The average COF values were compared at a sliding distance of 80 m. For alumina, the COF decreased from 0.75 for the non-lubricated coating to 0.19 for the alumina SLIPS. For stainless steel, the non-lubricated coating showed a COF value of 0.85. The stainless-steel SLIPS tests showed two different COF curve trends, so the results were divided into two groups for easier comparison. In the first group, the COF decreased to 0.20, while in the second group, it decreased to 0.41. Although some variation was observed between the stainless-steel SLIPS groups, both groups showed lower COF values than the non-lubricated stainless-steel coating. Overall, the SLIPS produced in this work showed clear potential for reducing the coefficient of friction under sliding contact. Therefore, thermally sprayed SLIPS can be considered a promising surface engineering approach for friction reduction in tribological applications.