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Chen, J., Björling, M., Marklund, P. & Shi, Y. (2024). Effect of anti-icing coating functional groups on ice adhesion. Applied materials today, 39, Article ID 102264.
Open this publication in new window or tab >>Effect of anti-icing coating functional groups on ice adhesion
2024 (English)In: Applied materials today, ISSN 2352-9407, Vol. 39, article id 102264Article in journal (Refereed) Published
Abstract [en]

Unwanted ice build-up is a ubiquitous phenomenon in nature, which creates a series of catastrophic impacts on a wide range of human activities. Various anti/de-icing materials have been proposed for dealing with icing issues. Superhydrophobic anti/de-icing coatings have been widely reported since it has high efficiency and can be achieved in different ways. The surface functional groups have a significant influence on surface energy which is related to surface wettability. However, the influence of the coating surfaces functional groups on the anti-/de-icing properties is still not well studied. To investigate this influence, different groups with different hydrophilicity have been introduced to 3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluorooctyl acrylate (TFOA) to fabricate several branch copolymer ice-phobic coatings. The anti-icing performance and the influence of group radius and interaction were studied. The acrylic acid TFOA showed a great superhydrophobic property (over 150° water contact angle), lower ice adhesion strength (<50 kPa), and lower wear depth compared with other copolymer coatings. The mechanism was studied via the molecular dynamic calculation carried out in ChemDraw software. The interaction between hydrophobic and hydrophilic groups and the steric length of the hydrophilic groups influence the surface structure and surface element distribution, further influencing the ice adhesion strength.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Radius, Hydrogen bond, van der Walls gap, Ice adhesion
National Category
Manufacturing, Surface and Joining Technology
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-105227 (URN)10.1016/j.apmt.2024.102264 (DOI)2-s2.0-85194943479 (Scopus ID)
Funder
Swedish Research Council Formas, 2019–00904, 2022–01988, 2022–01047Swedish Research Council, 2019–04941
Note

Validerad;2024;Nivå 2;2024-06-10 (hanlid);

Full text license: CC BY

Available from: 2024-04-24 Created: 2024-04-24 Last updated: 2024-06-10Bibliographically approved
Chen, J., Parsi, P. K., Marklund, P., Björling, M. & Shi, Y. (2024). Graphene-enhanced, wear-resistant and thermal-conductive, anti-/de-icing Gelcoat composite coating. Advanced Composites and Hybrid Materials, 7(1), Article ID 9.
Open this publication in new window or tab >>Graphene-enhanced, wear-resistant and thermal-conductive, anti-/de-icing Gelcoat composite coating
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2024 (English)In: Advanced Composites and Hybrid Materials, ISSN 2522-0128, Vol. 7, no 1, article id 9Article in journal (Refereed) Published
Abstract [en]

Wind power is considered as a sustainable and environmentally friendly energy source. However, the occurrence of icing poses significant challenges to energy production, particularly in frigid regions during the winter season. Conventional strategies employed for preventing and removing ice formation have proven inadequate due to their inability to satisfy intricate requirements or their high energy consumption. In this study, a commercial gelcoat coating was adopted as an anti-/de-icing coating by introducing different concentrations of graphene and boron nitride into the gelcoat coating through physical mixing. Extensive investigations were conducted on the correlation between anti-/de-icing, wear resistance, and thermal conductivity. Notably, the incorporation of nanoparticles induced a rise in the surface roughness, resulting in prolonged resistance to water icing on the coated surface. The wear resistance and thermal conductivity of the composite coating were enhanced through the inclusion of boron nitride and graphene. The building of thermal conductive particle networks improved thermal conductivity which can lead to improved heat transfer and heat distribution. At the same time, the enhanced gelcoat composite coating exhibited exceptional passive anti-/de-icing performance and wear resistance. This coating can replace commercial coatings to improve anti-/de-icing efficiency for the existing active heating anti-/de-icing techniques available in the market.

In this study, we aimed to enhance the wear resistance, thermal conductivity, and anti-/de-icing properties of a gelcoat composite coating by incorporating graphene and boron nitride. The gelcoat graphene coating showed better performance than the gelcoat boron nitride coating and pure gelcoat coating. The improved wear resistance of the gelcoat graphene coating can be attributed to the two-dimensional layer structure of graphene, while the addition of graphene resulted in a threefold increase in the thermal conductivity of the gelcoat composite coating compared to the pure gelcoat coating. The gelcoat composite coatings exhibited a high-water contact angle and low ice adhesive force. It was observed that as the surface roughness increased, the water contact angle also increased. The increase in ice adhesion after abrasion proves that abrasion is always detrimental to de-icing. Despite the extension of icing delay time, the large number of grooves and bumps created by wear results in stronger mechanical interlocking. It is worth mentioning that gelcoat graphene coating still demonstrated lower ice adhesive strength than gelcoat boron nitride coating and pure gelcoat coating. Overall, we successfully developed a gelcoat graphene coating with improved thermal conductivity, wear resistance, and low ice adhesive properties. This novel composite coating has the potential to significantly enhance the efficiency of existing heating technologies for anti-/de-icing applications, thereby reducing energy consumption associated with the turbine blades’ anti-/de-icing system.

Keywords
Graphene, Wear, Coating, Anti-/de-icing
National Category
Manufacturing, Surface and Joining Technology
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-103447 (URN)10.1007/s42114-023-00820-3 (DOI)2-s2.0-85181582111 (Scopus ID)
Funder
Swedish Research Council Formas, 2019–00904Swedish Research Council, 2019– 04941Swedish Energy Agency, 2018–003910Interreg Nord, 20202472
Note

Validerad;2024;Nivå 2;2024-04-02 (hanlid);

Full text license: CC BY 4.0

Available from: 2024-01-02 Created: 2024-01-02 Last updated: 2024-04-24Bibliographically approved
Marklund, P. & Pettersson, A. (2024). Lead-free 22lr ammunition for sport shooting: A simple implementation or a huge challenge?. Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology
Open this publication in new window or tab >>Lead-free 22lr ammunition for sport shooting: A simple implementation or a huge challenge?
2024 (English)In: Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, ISSN 1754-3371Article in journal (Refereed) Epub ahead of print
Abstract [en]

In Europe it is approximated that around six million people are active in sport shooting. Currently, most bullets are manufactured out of lead which in many cases is combined with a copper jacket. There are several reasons for using lead; lead is relatively cheap, soft, and has a high density, and is therefore often the ideal material for bullets. Currently, the EU is seeking a restriction or ban on the use of lead in firearm bullets, with the main motivation that hunting with lead bullets might result in lead poisoning of both animals and people. The proposed lead ban will also have a major impact on sport shooting, as it is likely to be subjected to the same regulations. One caliber that has been shown to be very difficult to produce as a lead-free alternative is 22lr (long rifle), which today is the most common caliber for sport shooting in many disciplines. Today, there are not many scientific investigations available which show the performance of lead versus lead-free ammunition in caliber 22lr, even though it would make sense to investigate the possibilities of designing lead-free ammunition before a possible lead ban is further discussed. In this work the performance of two common lead-free 22lr-cartridges is evaluated and shown in comparison with existing lead-based ammunition, with a primary focus on sport shooting. Performance has been evaluated under both summer and winter conditions to cover different sports shooting disciplines. The results of this study clearly show the difficulty of finding lead-free 22lr cartridges with acceptable performance on the market today. In fact, the performance of the tested lead-free ammunition is so poor that the EU’s proposed lead ban could completely ruin shooting as a sport due to a lack of functioning ammunition.

Place, publisher, year, edition, pages
Sage Publications, 2024
Keywords
Lead, lead-free, caliber, 22lr, .22, long rifle, ammunition, bullets, biathlon, shooting, shooting sports, accuracy, ballistics, impact, aiming, projectiles, physics of sports
National Category
Metallurgy and Metallic Materials Reliability and Maintenance
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-103456 (URN)10.1177/17543371231219379 (DOI)001134707600001 ()2-s2.0-85181200234 (Scopus ID)
Note

Full text license: "Under Sage's Green Open Access policy, the Accepted Version of the article may be posted in the author's institutional repository and reuse is restricted to non-commercial and no derivative uses."

Available from: 2024-01-03 Created: 2024-01-03 Last updated: 2024-03-12
Johansson, P., Marklund, P., Björling, M. & Shi, Y. (2024). Mechanisms behind the environmental sensitivity of carbon fiber reinforced polytetrafluoroethylene (PTFE). Friction, 12(5), 997-1015
Open this publication in new window or tab >>Mechanisms behind the environmental sensitivity of carbon fiber reinforced polytetrafluoroethylene (PTFE)
2024 (English)In: Friction, ISSN 2223-7690, E-ISSN 2223-7704, Vol. 12, no 5, p. 997-1015Article in journal (Refereed) Published
Abstract [en]

Carbon fiber reinforced polytetrafluoroethylene (CF/PTFE) composites are known for their exceptional tribological performance when sliding against steel or cast iron in inert gas environments. Compared to experiments in humid air, about an order of magnitude lower wear rate and several times lower coefficient of friction have been reported for tests conducted in dry nitrogen and hydrogen. Moreover, trace moisture has been shown to affect the friction and wear significantly of this tribosystem, although a possible effect of oxygen cannot be ruled out due to uncertainties regarding the oxygen concentrations. While several studies have pointed out the environmental sensitivity of CF/PTFE, the understanding of the underlying mechanisms are very limited. The objective of this research is to investigate the individual and combined effect of oxygen and moisture on the tribological behavior of CF/PTFE sliding against steel. Additionally, this study aims to elucidate the underlying mechanisms that govern the environmental sensitivity of the system. Climate-controlled three-pin-on-disc experiments were conducted in nitrogen atmospheres at various concentrations of oxygen and moisture. The tribological results clearly demonstrate that both moisture and oxygen contribute to increased friction and wear. However, the adverse effect was much more pronounced for oxygen than moisture. A qualitative method was developed to estimate the tribofilm coverage on the CF/PTFE surface. Results showed strong correlation between high coverage of strongly adhered tribofilm and low wear rate. Moreover, a loosely adhered tribofilm was observed on top of the CF/PTFE surface in presence of moisture. FTIR analysis indicated that the loosely adhered tribofilm found in the moisture-enriched environment contained a significant amount of adsorbed water, which may explain the lower coefficient of friction in presence of moisture compared to oxygen. The adsorbed water in the loosely adhered tribofilm could be an indication of moisture-driven lubrication by the non-graphitic carbon in the tribofilm.

Place, publisher, year, edition, pages
Springer Nature, 2024
Keywords
polymer composite, tribofilm, tribochemistry, atmosphere
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-101605 (URN)10.1007/s40544-023-0824-9 (DOI)001113623800003 ()2-s2.0-85178446936 (Scopus ID)
Note

Validerad;2024;Nivå 2;2024-04-02 (hanlid);

Full text license: CC BY 4.0

Available from: 2023-10-09 Created: 2023-10-09 Last updated: 2024-04-02Bibliographically approved
Mehamud, I., Björling, M., Marklund, P. & Shi, Y. (2024). Self-powered online practical machine condition monitoring and wireless communication achieved on integrated, efficient, and durable triboelectric nanogenerator. Nano Energy, 123, Article ID 109439.
Open this publication in new window or tab >>Self-powered online practical machine condition monitoring and wireless communication achieved on integrated, efficient, and durable triboelectric nanogenerator
2024 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 123, article id 109439Article in journal (Refereed) Published
Abstract [en]

Triboelectric nanogenerator (TENG) can effectively scavenge ambient mechanical energy with cost, weight, and effectiveness advantages despite critical issues of TENG such as integration to complex components, low current output, and durability. In this work, we designed an adaptive TENG on a mechanical shaft for harvesting rotational energy which can easily assemble and disassemble. The proposed TENG presents an excellent performance for a wide range of rotational speeds (0–2000rpm) and delivers a high power of up to about 80mW (a high short circuit current of 3mA) for a size of 216 cm3, which is high enough for many types of machine condition monitoring purposes. The designed TENG has been evaluated under the noncontact mode of operation within a 0–0.5mm gap between TENG films. The TENG demonstrates excellent electrical stability of 99% without surface wear under noncontact mode within the whole test period for continuous operation of 420,000 cycles. The contact mode with a contact pressure of 0.76 Pa results in 90% electrical stability and apparent surface degradation. Moreover, it is demonstrated that the proposed TENG can power a wireless vibration sensor (60 mW) within 10 minutes energy harvesting for 9 seconds to send data via Bluetooth to a smartphone at up to 30 m, and a wireless temperature sensor (1.2 mW) in real-time for machine condition monitoring.

Place, publisher, year, edition, pages
Elsevier, 2024
Keywords
Condition monitoring, Durability, Energy harvesting, TENG, Triboelectric nanogenerator, Wireless communication
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-104623 (URN)10.1016/j.nanoen.2024.109439 (DOI)2-s2.0-85186960197 (Scopus ID)
Funder
Swedish Research Council Formas, 2019–00904Swedish Research Council, 2019–04941, 2023–04962
Note

Validerad;2024;Nivå 2;2024-03-18 (hanlid);Full text license: CC BY

Available from: 2024-03-18 Created: 2024-03-18 Last updated: 2024-03-18Bibliographically approved
Strömbergsson, D., Kumar, A., Marklund, P. & Sandin, F. (2023). Co-design Model for Neuromorphic Technology Development in Rolling Element Bearing Condition Monitoring. In: Chetan S. Kulkarni; Indranil Roychoudhury (Ed.), Proceedings of the Annual Conference of the PHM Society 2023: . Paper presented at 15th Annual Conference of the Prognostics and Health Management Society (PHM), October 28th – November 2nd, 2023, Salt Lake City, Utah, USA. PHM Society
Open this publication in new window or tab >>Co-design Model for Neuromorphic Technology Development in Rolling Element Bearing Condition Monitoring
2023 (English)In: Proceedings of the Annual Conference of the PHM Society 2023 / [ed] Chetan S. Kulkarni; Indranil Roychoudhury, PHM Society , 2023Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents an end-to-end condition monitoring co-design model, from vibration measurement to anomaly detection, where conventional signal processing principles are combined with neuromorphic sensing and computing concepts to enable investigations of the potential improvements offered by brain-like information processing technologies.

The use of machine learning in condition monitoring became increasingly popular for intelligent fault diagnosis in the last decade, taking advantage of the rapid developments in deep learning.

However, the high computational cost of training and using deep neural networks prevents the use of such solutions for analysing the bulk of data generated by the resource constrained edge devices, i.e., the condition monitoring sensor systems, as only a minor fraction of data can be transmitted to the cloud or edge servers for analysis.

There is an untapped potential to process this data and thereby improve intelligent fault diagnosis models using event-triggered sensing, spiking neural networks, and neuromorphic processors that substantially can improve the energy efficiency and capacity of embedded machine learning condition monitoring solutions.

The proposed co-design model is evaluated on two use-cases involving rolling element bearing failures, one based on a labelled laboratory environment dataset, and one based on a wind turbine drivetrain bearing failure representing a real-world scenario with stochastic changes of machine state and unknown labels of the bearing condition.

By adjusting co-design parameters, the resulting hybrid conventional/neuromorphic model show a comparable accuracy in detection performance for the laboratory dataset compared to the state-of-the-art reported in the literature.

Similarly, for the wind turbine drivetrain dataset a bearing fault detection time comparable to that in previous work is obtained.

This shows the successful implementation of a hybrid conventional/neuromorphic co-design model for condition monitoring applications, offering novel opportunities to investigate performance trade-offs and efficiency improvements enabled by neuromorphic technologies.

Place, publisher, year, edition, pages
PHM Society, 2023
Series
Annual Conference of the PHM Society (PHM), ISSN 2325-0178 ; 15:1
Keywords
neuromorphic computing, spiking neural networks
National Category
Other Mechanical Engineering
Research subject
Machine Learning; Machine Elements
Identifiers
urn:nbn:se:ltu:diva-103095 (URN)10.36001/phmconf.2023.v15i1.3494 (DOI)2-s2.0-85178330102 (Scopus ID)
Conference
15th Annual Conference of the Prognostics and Health Management Society (PHM), October 28th – November 2nd, 2023, Salt Lake City, Utah, USA
Funder
The Kempe Foundations, SMK21-0046, JCSMK JF-2303Luleå University of Technology
Note

Full text license: CC BY;

ISBN for host publication: 978-1-936263-29-5

Available from: 2023-11-29 Created: 2023-11-29 Last updated: 2024-01-24Bibliographically approved
Johansson, P., Marklund, P., Björling, M. & Shi, Y. (2023). Effect of Oxygen and Moisture on the Friction and Wear of Carbon Fiber-Reinforced Polymers. Lubricants, 11(9), Article ID 412.
Open this publication in new window or tab >>Effect of Oxygen and Moisture on the Friction and Wear of Carbon Fiber-Reinforced Polymers
2023 (English)In: Lubricants, ISSN 2075-4442, Vol. 11, no 9, article id 412Article in journal (Refereed) Published
Abstract [en]

Carbon fiber-reinforced polytetrafluoroethylene (CF/PTFE) composites are frequently used in tribological dry gas applications, such as in dynamic seals in reciprocating hydrogen gas compressors and Stirling engines, due to their superior friction and wear. Due to the increasing concerns regarding fluoropolymers as possible pollutants of harmful per- and poly-fluoroalkyl substances (PFAS) emissions, replacements for PTFE should be investigated. The literature indicates that CF-reinforced polyetheretherketone (CF/PEEK) may have similar favorable tribological properties to CF/PTFE. However, the tribological behavior of CF/PEEK in dry gas is poorly understood, and no direct comparison has been made between the two materials. The aim of this study was to compare the effect of oxygen and moisture on the friction and wear of CF/PTFE and CF/PEEK. Tribological tests were carried out with a tri-pin-on-disc tribometer in a nitrogen environment with individually controlled contents of oxygen and moisture. The results showed that the effect of oxygen and moisture are distinctly different for CF/PTFE and CF/PEEK. While CF/PTFE performs best in oxygen-deficient environments, CF/PEEK performs best in moisture-enriched environments. Complementary tests with a PTFE composite filled with both CF and PEEK suggested that the environmental sensitivity can be significantly reduced by combining the two polymers.

Place, publisher, year, edition, pages
MDPI, 2023
Keywords
polymer composite, dry gas, environment, ultralow wear
National Category
Applied Mechanics
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-101549 (URN)10.3390/lubricants11090412 (DOI)001145273900001 ()2-s2.0-85172472664 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-10-03 (joosat);

Available from: 2023-10-03 Created: 2023-10-03 Last updated: 2024-03-07Bibliographically approved
Kumar, A., Strömbergsson, D., Marklund, P. & Sandin, F. (2023). Exploring Filter Banks and Spike Interval Statistics of Level-Crossing ADCs for Fault Diagnosis of Rolling Element Bearings. In: Chetan S. Kulkarni; Indranil Roychoudhury (Ed.), Proceedings of the Annual Conference of the PHM Society 2023: . Paper presented at 15th Annual Conference of the Prognostics and Health Management Society (PHM), October 28th – November 2nd, 2023, Salt Lake City, Utah, USA. PHM Society
Open this publication in new window or tab >>Exploring Filter Banks and Spike Interval Statistics of Level-Crossing ADCs for Fault Diagnosis of Rolling Element Bearings
2023 (English)In: Proceedings of the Annual Conference of the PHM Society 2023 / [ed] Chetan S. Kulkarni; Indranil Roychoudhury, PHM Society , 2023Conference paper, Published paper (Refereed)
Abstract [en]

Nowadays, lots of data are generated in industries using vibration sensors to evaluate the equipment’s working condition and identify faults. A significant challenge is that only a small fraction of data can be transmitted for intelligent fault diagnosis and storage. The edge processing capacity is often insufficient for advanced analysis due to time and resource constraints. The neuromorphic signal encoding scheme efficiently reduces the data rate by encoding relevant signal changes into spike trains while discarding redundant information and noise, enabling energy-efficient neuromorphic processing. Due to the presence of dominant operational features and noise in the original measurements, signal pre-processing is required to extract the relevant features before spike coding and processing. The work investigates the effects of different filter banks (pre-processing methods) on the spike encodings for vibration measurements from bearings. This also includes bearing fault features diagnosis based on statistical analysis of generated spikes. The comparative analysis is made for benchmarking different signal pre-processing methods (e.g., envelope, empirical mode decomposition (EMD), and gammatone filter) on bearing vibration datasets. An event-triggered scheme, i.e., Level-crossing analog-to-digital converters (LC-ADCs) is applied to encode the vibration measurement to spikes. Inter-spike intervals (ISIs) statistics are analysed for fault diagnosis of bearings. The results obtained for CWRU bearing databases indicate a possible fault detection and diagnosis with significant data rate reduction and an opportunity for improved computational efficiency. With the developed approach, the envelope filter is found to be the most efficient of all. This work enables a new approach to improve the energy efficiency of condition monitoring systems and further sets a new course of research development in this area using neuromorphic technologies. 

Place, publisher, year, edition, pages
PHM Society, 2023
Series
Annual Conference of the PHM Society (PHM), ISSN 2325-0178 ; 15:1
Keywords
Fault Diagnosis, neuromorphic processing, Interspike interval (ISI), Bearing, vibration
National Category
Other Mechanical Engineering
Research subject
Machine Elements; Machine Learning
Identifiers
urn:nbn:se:ltu:diva-103109 (URN)10.36001/phmconf.2023.v15i1.3493 (DOI)2-s2.0-85178354777 (Scopus ID)
Conference
15th Annual Conference of the Prognostics and Health Management Society (PHM), October 28th – November 2nd, 2023, Salt Lake City, Utah, USA
Funder
Luleå University of TechnologyThe Kempe Foundations, SMK21-0046, JCSMK JF-2303
Note

Full text license: CC BY;

ISBN for host publication: 978-1-936263-29-5

Available from: 2023-11-30 Created: 2023-11-30 Last updated: 2024-01-24Bibliographically approved
Johansson, P., Elo, R., Fadaei Naeini, V., Marklund, P., Björling, M. & Shi, Y. (2023). Insights of the Ultralow Wear and Low Friction of Carbon Fiber Reinforced PTFE in Inert Trace Moisture Environment. Tribology letters, 71(3), Article ID 100.
Open this publication in new window or tab >>Insights of the Ultralow Wear and Low Friction of Carbon Fiber Reinforced PTFE in Inert Trace Moisture Environment
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2023 (English)In: Tribology letters, ISSN 1023-8883, E-ISSN 1573-2711, Vol. 71, no 3, article id 100Article in journal (Refereed) Published
Abstract [en]

Ultralow wear rates and low friction have been observed for carbon fiber reinforced PTFE (CF/PTFE) when sliding against steel or cast iron in dry gas environments. Although the strong environmental sensitivity of this tribosystem is well known, the origin of the outstanding tribological performance in dry gas remains unanswered. Some researchers attribute the low friction and wear to the formation of carbon-rich surfaces in the absence of oxygen and moisture in the environment. However, low friction between carbon surfaces is generally dependent on moisture. In this paper, extensive analyzes are conducted on the tribofilms formed on the CF/PTFE surface and the steel counterface after sliding in a high-purity nitrogen environment. TEM analysis of a cross-section of the tribofilm on the steel surface reveals that the sliding surface consists mainly of iron (II) fluoride and not carbon, even though a significant amount of carbon was observed near the surface. XPS and TEM analysis further revealed that the tribofilm formed on the worn composite surface consisted of nanoparticle agglomerates, anchored to the PTFE matrix and to each other by carbon with turbostratic structure. Turbostratic carbon also formed an ultrathin and surface-oriented superficial layer on top of the agglomerates. Governing mechanisms of the low friction and wear of the CF/PTFE—steel tribosystem were investigated by complementary tribotests with pure graphite samples and MD simulations of the identified surfaces. These indicated that the low friction between the carbon and iron fluoride in the tribofilms is due to poor adhesion between the distinctly different surfaces.

Place, publisher, year, edition, pages
Springer, 2023
Keywords
Self-lubricating composite, Tribochemistry, Friction mechanisms, TEM, XPS
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Elements; Applied Physics
Identifiers
urn:nbn:se:ltu:diva-99263 (URN)10.1007/s11249-023-01770-z (DOI)001041863500002 ()2-s2.0-85167413955 (Scopus ID)
Note

Validerad;2023;Nivå 2;2023-08-07 (joosat);

Licens fulltext: CC BY License

Available from: 2023-08-07 Created: 2023-08-07 Last updated: 2024-03-07Bibliographically approved
Chen, J., Marklund, P., Björling, M. & Shi, Y. (2023). In-situ polymerized siloxane urea enhanced graphene-based super-fast, durable, all-weather elec-photo-thermal anti-/de-icing coating. Journal of Science: Advanced Materials and Devices, 8(3), Article ID 100604.
Open this publication in new window or tab >>In-situ polymerized siloxane urea enhanced graphene-based super-fast, durable, all-weather elec-photo-thermal anti-/de-icing coating
2023 (English)In: Journal of Science: Advanced Materials and Devices, ISSN 2468-2284, Vol. 8, no 3, article id 100604Article in journal (Refereed) Published
Abstract [en]

Previous investigations on anti-/de-icing techniques have primarily focused on mild laboratory conditions, which have limited practical applicability due to their short service life. Consequently, there is an urgent demand for the development of durable anti-/de-icing technologies capable of withstanding complex environmental conditions. In this research endeavour, we have successfully formulated a hydrophobic coating based on graphene. To circumvent the challenges associated with environmentally unfriendly organic solvents, we utilized a graphene water slurry as the foundational material and subsequently incorporated a poly (vinyl alcohol)-water solution. The resulting solution was subjected to in situ polymerization of a siloxane urea crosslinked polymer, yielding the desired coating solution. Following a solution spraying and drying process, the ultimate product obtained was the hydrophobic conductive graphene (HCG) siloxane Coating. The HCG siloxane Coating exhibits a conductivity of 66 S/m, enabling it to melt ice droplets within a mere 10 s, whereas conventional coatings require 20–500 s for the same task. A comprehensive field test conducted during an entire winter period on a high mountain situated within the Arctic Circle in Finland demonstrated the excellent anti-icing properties of the developed coating when subjected to approximately 310 W/m2 power. Furthermore, the coating exhibited satisfactory de-icing performance under approximately 570 W/m2 power, successfully removing ice accumulations within approximately 10 min. Throughout the field test, temperatures frequently plummeted to −20 °C, accompanied by wind speeds reaching up to 12 m/s. Material characterization revealed that the micro-nano structure of the coating surface, which engenders favourable hydrophobic behaviour, was primarily attributed to the phase separation resulting from hydrophilic and hydrophobic interactions. Moreover, the semi-interpenetrating structure formed by the polyvinyl alcohol molecular chains and in-situ polymerized siloxane urea ensured the coating's strength.

Place, publisher, year, edition, pages
Elsevier, 2023
Keywords
Anti-/de-icing, Coating, Conductive, Graphene
National Category
Materials Chemistry
Research subject
Machine Elements
Identifiers
urn:nbn:se:ltu:diva-99303 (URN)10.1016/j.jsamd.2023.100604 (DOI)2-s2.0-85165422965 (Scopus ID)
Funder
Swedish Research Council Formas, 2019-00904Swedish Research Council, 2019-04941Swedish Energy Agency, 2018-003910Interreg Nord
Note

Validerad;2023;Nivå 2;2023-08-09 (hanlid)

Available from: 2023-08-09 Created: 2023-08-09 Last updated: 2024-04-24Bibliographically approved
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