Browsing by Author "Rosenkranz, Andreas"

Now showing 1 - 20 of 37
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    2D materials for Tribo-corrosion and -oxidation protection: a review
    (Elsevier B.V., 2024) Ramteke, Sangharatna M.; Walczak, Magdalena; De Stefano, Marco; Ruggiero, Alessandro; Rosenkranz, Andreas; Marian, Max
    The recent rise of 2D materials has extended the opportunities of tuning a variety of properties. Tribo-corrosion, the complex synergy between mechanical wear and chemical corrosion, poses significant challenges across numerous industries where materials are subjected to both tribological stressing and corrosive environments. This intricate interplay often leads to accelerated material degradation and failure. This review critically assesses the current state of utilizing 2D nanomaterials to enhance tribo-corrosion and -oxidation behavior. The paper summarizes the fundamental knowledge about tribo-corrosion and -oxidation mechanisms before assessing the key contributions of 2D materials, including graphene, transition metal chalcogenides, hexagonal boron nitride, MXenes, and black phosphorous, regarding the resulting friction and wear behavior. The protective roles of these nanomaterials against corrosion and oxidation are investigated, highlighting their potential in mitigating material degradation. Furthermore, we delve into the nuanced interplay between mechanical and corrosive factors in the specific application of 2D materials for tribo-corrosion and -oxidation protection. The synthesis of key findings underscores the advancements achieved through integrating 2D nanomaterials. An outlook for future research directions is provided, identifying unexplored avenues, and proposing strategies to propel the field forward. This analysis aims at guiding future investigations and developments at the dynamic intersection of 2D nanomaterials, tribo-corrosion, and -oxidation protection.
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    A critical assessment of surface texturing for friction and wear improvement
    (2017) Gachot, C.; Rosenkranz, Andreas; Hsu, S. M.; Costa, H. L.
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    Additive Manufacturing in the Maritime Industry: A Perspective on Current Trends and Future Needs
    (2023) Garofalo, James; Shah, Raj; Thomas, Gavin; Shirvani, Khosro; Marian, Max; Rosenkranz, Andreas
    Additive manufacturing (AM) has seen slow growth thus far in the maritime industry. Like other industries, maritime companies and institutions have started using AM for prototyping and product development needs but is now beginning to expand into production of end use parts and production tooling. The slow adoption can mainly be attributed to a previous lack of education in additive technology and strategies, current lack of reliability testing of additive machines in a marine environment, and the need for classification and certification of parts and machines before shipowners and crews will likely adopt for widespread use. This article provides a perspective of recent AM activities within the industry and discusses the need for research in key areas before widespread utilization can occur. Current use includes a recent push in maritime education, surveys of maritime workers and stakeholders, and fabrication of replacement parts, propellers, and boat hulls. Prospective key areas with the need for further research include 1) use-cases for replacement parts on ship, 2) economic feasibility of putting 3D printers on board, 3) standards, certification, and quality assurance, and 4) reliability and repeatability in a marine environment
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    Additively manufactured MAX- and MXene-composite scaffolds for bone regeneration- recent advances and future perspectives
    (2023) Khabisi, Minufar Abdollahi; Shirini, Farhad; Shirini, Kasra; Khorsand, Hamid; Marian, Max; Rosenkranz, Andreas
    Human bones can suffer from various injuries, such as fractures, bone cancer, among others, which has initiated research activities towards bone replacement using advanced bio-materials. However, it is still challenging to design bio-scaffolds with bone-inducing agents to regenerate bone defects. In this regard, MAX-phases and MXenes (early transition metal carbides and/or nitrides) have gained notable attention due to their unique hydrophilicity, bio-compatibility, chemical stability, and photothermal properties. They can be used in bone tissue engineering as a suitable replacement or reinforcement for common bio-materials (polymers, bio-glasses, metals, or hydroxyapatite). To fabricate bio-scaffolds, additive manufacturing is prospective due to the possibility of controlling porosity and creating complex shapes with high resolution. Until now, no comprehensive article summarizing the existing state-of-the-art related to bone scaffolds reinforced by MAX-phases and MXenes fabricated by additive manufacturing has been published. Therefore, our article addresses the reasons for using bone scaffolds and the importance of choosing the most suitable material. We critically discuss the recent developments in bone tissue engineering and regenerative medicine using MAX-phases and MXenes with a particular emphasis on manufacturing, mechanical properties, and bio-compatibility. Finally, we discuss the existing challenges and bottlenecks of bio-scaffolds reinforced by MAX-phases and MXenes before deriving their future potential.
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    Bio-tribological characterization of additives in synovial fluid - usage of graphene, Ti3C2Tx and their synergistic effects
    (2025) Ramteke R., Sangharatna Munneshwar; Ugarte Muñoz, Alfonso E.; Zambrano, Dario F.; Ramos Grez, Jorge; Rosenkranz, Andreas; Marian, Max
    Synovial joints play a crucial role in limb biomechanics, depending on advanced lubrication systems to reduce wear. However, disruptions caused by injury or disease often led to the need for joint replacements. Although additive manufacturing enables the production of customized implants, achieving optimal wear resistance is still a significant challenge. This research explores the use of nano-additives in synovial fluid (SF). In this context, we examine the dispersion stability, surface wettability, dynamic viscosity, and bio-tribological behavior of SF enhanced by graphene (G), MXene (Ti3C2Tx), and their hybrid (G-Ti3C2Tx) in the concentrations of 0.5, 2, and 10 mg/mL, respectively. Results show that G and the hybrid maintained stable dispersions in SF, while Ti3C2Tx shows slight sedimentation at lower concentrations. Both G and Ti3C2Tx substantially improved wettability, with the most pronounced effect observed at 10 mg/mL for Ti3C2Tx (29.8 % reduction in contact angle). The bio-tribological analysis indicates that the hybrids induced a superior wear resistance (78.3 % wear reduction at 2 mg/mL). These findings highlight the potential of hybrid, in enhancing the bio-tribological properties of SFs, which is highly prospective to enhance knee prostheses and arthritis management.
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    Biomass-derived furfural conversion over Ni/CNT catalysts at the interface of water-oil emulsion droplets
    (2020) Herrera, C.; Pinto-Neira, J.; Fuentealba Patiño, Denis Alberto; Sepulveda, C.; Rosenkranz, Andreas; Gonzalez, M.; Escalona, Néstor
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    Biotribological Performance of Multilayer Ti- and Mo-Based MXene Coatings
    (2025) Ramteke R., Sangharatna Munneshwar; Molina, Ricardo; Zambrano, Dario F.; Marian, Max; Rosenkranz, Andreas
    Metallic materials are extensively utilized in biomedical implants due to their excellent strength and corrosion resistance. However, friction and wear-related issues remain important challenges in load-bearing implant applications. To address these concerns, multilayer Ti3C2T x , Mo2TiC2T x , and Mo2Ti2C3T x coatings were deposited onto stainless steel substrates in two distinct thickness ranges (lower: similar to 100 to 150 nm; higher: similar to 225 to 275 nm) and biotribologically tested under simulated body fluid lubrication conditions. Our results revealed that low coating thicknesses of Mo2TiC2T x demonstrated the most favorable biotribological performance, reducing the wear rate by up to 33% and consistently lowering the coefficient of friction, with reductions of up to 56% compared to uncoated references, owing to their ability to form durable tribo-films under SBF lubrication. In contrast, Ti3C2T x coatings increased friction and wear under considered conditions, while Mo2Ti2C3T x showed a moderate COF reduction but higher wear rates, particularly at higher coating thicknesses and loads. These findings emphasize the superior self-lubricating properties of Mo2TiC2T x coatings, thus highlighting their potential to enhance the durability and longevity of load-bearing biomedical implants.
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    Catalytic performance of 2D-Mxene nano-sheets for the hydrodeoxygenation (HDO) of lignin-derived model compounds
    (2020) Blanco, E; Rosenkranz, Andreas; Espinoza-González, R; Fuenzalida, VM; Zhang, ZY; Suarez, S.; Escalona, N.
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    Combining multi-scale surface texturing and DLC coatings for improved tribological performance of 3D printed polymers
    (2023) Marian, Max; Zambrano, Dario F.; Rothammer, Benedict; Waltenberger, Valentin; Boidi, Guido; Krapf, Anna; Merle, Benoit; Stampfl, Jürgen; Rosenkranz, Andreas; Gachot, Carsten; Grützmacher, Philipp G.
    Polymer components fabricated by additive manufacturing typically show only moderate strength and low temperature stability, possibly leading to severe wear and short lifetimes especially under dry tribological sliding. To tackle these shortcomings, we investigated the combination of single- and multi-scale textures directly fabricated by digital light processing with amorphous diamond-like carbon (DLC) coatings. The topography of the samples and conformity of the coatings on the textures are assessed and their tribological behaviour under dry conditions is studied. We demonstrate that the surface textures have a detrimental tribological effect on the uncoated samples. This changes with the application of DLC coatings since friction substantially reduces and wear of the textures is not observed anymore. These trends are attributed to the protection of the underlying polymer substrate by the coatings and a reduced contact area. The best tribological performance is found for a coating with highest hardness and hardness-to-elasticity ratios. Moreover, multi-scale textures perform slightly better than single-scale textures due to a smaller real contact area. Summarizing, we verified that the high flexibility and low production costs of 3D printing combined with the excellent mechanical and tribological properties of DLC results in synergistic effects with an excellent performance under dry sliding conditions
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    Depolymerization and Nanoliposomal Encapsulation of Grape Seed Condensed Tannins: Physicochemical Characterization, Stability, In Vitro Release and Bioaccessibility
    (MDPI, 2025) Morales, Carolina F.; Zamorano, Marcela; Brossard Aravena, Natalia Daniela; Rosenkranz, Andreas
    Condensed tannins from grape seed residues show high antioxidant activity but low oral bioavailability because of their high degree of polymerization and covalent interactions with proteins. This study aimed to improve their bioaccessibility through depolymerization and encapsulation. Depolymerization was carried out using microwave-assisted SN1 reactions with gallic acid as a nucleophile under food-grade conditions, mainly producing epicatechin monomers with 99.8% polymer degradation efficiency. Importantly, the inhibition of ABTS●+ and DPPH● radicals remained unaffected (p > 0.05), indicating that depolymerization preserved the antioxidants’ redox function, maintaining about 90% of their inhibition activity. The products were encapsulated in phosphatidylcholine liposomes, which had nanometric sizes and high encapsulation efficiency (83.11%), and remained stable for up to 60 days. In vitro release of nanoliposomal epicatechin in a D1 simulant was less than 10% after 48 h, fitting a Weibull model (β = 0.07), suggesting sub-diffusive transport and demonstrating high bioactive retention capacity in aqueous systems. During in vitro digestion, bioaccessibility of gallic acid and epicatechin reached 95.61 ± 0.58% and 98.56 ± 0.81%, respectively, with a 2333% increase in the bioaccessible mass of flavan-3-ols in native liposomal condensed tannins, which otherwise showed no detectable bioaccessibility. These findings highlight the potential of polyphenols from agro-industrial waste with enhanced bioaccessibility for applications in nutraceuticals and functional foods.
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    Effect of Ni Metal Content on Emulsifying Properties of Ni/CNTox Catalysts for Catalytic Conversion of Furfural in Pickering Emulsions
    (2021) Herrera Hernández, Carla Pía; Pinto Neira, Josefa; Fuentealba Patiño, Denis Alberto; Sepúlveda, C.; Rosenkranz, Andreas; García-Fierro, J. L.; González, M.; Escalona, Néstor
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    Effects of Ti3C2Tx nano-sheets (MXenes) on the microstructural and electrochemical properties of SnO2/Ti anodes
    (2021) Gonzalez-Poggini, Sergio; Rosenkranz, Andreas; Wang, Bo; Hevia, Samuel; Yu, Jinhong; Colet-Lagrille, Melanie
    The effects of the incorporation of Ti3C2Tx nano-sheets (MXenes) on the microstructure of SnO2/Ti electrodes and their electro-oxidation catalytic activity for the degradation of methyl red is studied in this work. MXenes-SnO2/Ti electrodes are fabricated by spin-coating followed by a thermal treatment under ambient atmospheric conditions using a solution containing MXene nano-sheets, SnCl2, citric acid and ethylene glycol as precursor. Energy-dispersive X-ray spectroscopy, Raman spectroscopy and Xray diffraction analyses of the MXenes-SnO2/Ti electrodes surface indicate the formation of SnO2-TiO2 films with Ti4+ ions incorporated into the lattice of SnO2 crystals. Cyclic voltammetry curves demonstrate that the oxygen evolution reaction is restrained by the MXenes-SnO2/Ti electrodes, while the methyl red electro-oxidation is enhanced - with kinetics following a pseudo-first-order model compared to the performance of (pure) SnO2/Ti electrodes. These results suggest that oxygen vacancies are formed in the crystal lattice of MXenes-SnO2/Ti electrodes, which act as charge carriers and increase the electrical conductivity of SnO2 as confirmed by the lower charge transfer resistance of MXenes-SnO2/Ti electrodes determined by electrochemical impedance spectroscopy analysis.
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    Enhancing mechanical and biomedical properties of protheses - Surface and material design
    (2021) Raj Shah; Blerim Gashi; Sharika Hoque; Max Marian; Rosenkranz, Andreas
    The long-term success of prosthetics greatly relies on the biomechanical/medical properties of the implanted material. Inadequate biocompatibility or poor wear resistance can lead to devastating repercussions including osteolysis, tissue inflammation, and implant failure, which require revisionary surgery, thus being costly and painful for the patient. Therefore, special attention has been given to the modification/treatment of prosthetic surfaces to enhance cell proliferation and bio-tribological performance as well as to improve tendon-growth and mobility. The advanced usage of porous structures and surface textures represents an innovative approach towards promoting the growth of healthy soft tissue rather than cicatricial tissue as well as enhancing wear and the lubricative performance. Other prosthetic surface modifications including plasma immersion ion implantation (PIII), the application of bio-tribologically effective coatings or the introduction of carbon nanotubes (CNTs) as reinforcement have also emerged. The identification of the optimal prosthetic materials (UHMWPE, HXLPE, Ti6Al4V, or CoCrMo) as well as the application of relevant surface modifications or treatments serves as a vital opportunity in enhancing the protheses’ longevity and performance. Therefore, this article seeks to compile recent and fundamental research trends surrounding these methods with a special emphasis towards improving the tribological properties, cell proliferation, and overall prosthetic success of biomaterials.
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    Evaluation of DLC, MoS2, and Ti3C2T thin films for triboelectric nanogenerators
    (2022) Tremmel, Stephan; Luo, Xiongxin; Rothammer, Benedict; Seynstahl, Armin; Wang, Bo; Rosenkranz, Andreas; Marian, Max|Zhu, Laipan
    Due to their cost-effective fabrication, easy integration, and low frequency working range, triboelectric nanogenerators (TENGs) demonstrate tremendous potential in green energy harvesting to power smart devices and the internet of things (IoT). However, there is an urgent need to synergistically maximize their output and improve their durability to ensure a long-lasting high performance. This study aims at elucidating the performance of protective thin films deposited on the wear-prone PTFE surface of TENGs including doped and undoped, single- and multi-layer hydrogenated DLC films, MoS2 coatings fabricated by physical vapor deposition and multi-layer Ti3C2Tx (MXene) films. The deposited coatings are characterized by electron microscopy, and Raman spectroscopy. Their triboelectric performance is analyzed for TENGs operating in contact separation and freestanding sliding modes. We verified that MXenes outperformed the other films in contact separation mode due to the good electron gain ability of functional oxygen and fluorine groups. In sliding mode, the undoped a-C:H coating performed on a comparable level to the uncoated reference and superior to the tungsten-doped DLC and MoS2 films. The film withstood long-term tests without notable signs of wear; merely the output slowly decreased with time due to graphitization and thus potential material transfer to the mating body.
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    Evaluation of the surface fatigue behavior of amorphous carbon coatings through cyclic nanoindentation
    (2021) Weikert, Tim; Wartzack, Sandro; Baloglu, Maximiliano V.; Willner, Kai; Gabel, Stefan; Merle, Benoit; Pineda, Fabiola; Walczak, Magdalena; Marian, Max; Rosenkranz, Andreas; Tremmel, Stephan
    Diamond-like carbon (DLC) coatings, frequently used to reduce wear and friction in machine components as well as on forming tools, are often subjected to cyclic loading. Doping of DLC coatings with metals or metal carbides as well as the usage of multilayer architectures represent promising approaches to enhance toughness, which is beneficial for the coatings' behavior under cyclic loading. In this study, we utilized cyclic nanoindentation to characterize the tribologically induced surface fatigue behavior of single-layer tungsten-doped (a-C:H:W) and multilayer silicon oxide containing (a-C:H:Si:O/a-C:H)25 amorphous carbon coatings under cyclic loading. Columnar growth was observed for both coatings by focused ion beam microscopy and scanning electron microscopy, while the multilayer architecture of the (a-C:H:Si:O/a-C:H)25 coating was verified by the silicon content using glow-discharge optical emission spectroscopy. In cyclic nanoindentation of the (a-C:H:Si:O/a-C:H)25 multilayer coating, stepwise small changes in indentation depth were observed over several indentation cycles. The surface fatigue process of the single-layer a-C:H:W covered a smaller number of indentation cycles and was characterized by an early steep increase of the static displacement signal. Microscopical analyses hint at grain deformation, sliding at columnar boundaries, and grain detachment as underlying fatigue mechanisms of the a-C:H:W coating, while the (a-C:H:Si:O/a-C:H)25 multilayer coating showed transgranular crack propagation and gradual fracturing. In case of the (a-C:H:Si:O/a-C:H)25 multilayer coating, superior indentation hardness (HIT) and indentation modulus (EIT) as well as a higher HIT3/EIT2 ratio suggest a higher resistance to plastic deformation. A high HIT3/EIT2 ratio, being an indicator for hindered crack initiation, combined with the capability of stress relaxation in soft layers contributed to the favorable surface fatigue behavior of the (a-C:H:Si:O/a-C:H)25 multilayer coating observed in this cyclic nanoindentation studies
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    Failure Analysis of Slurry Pump Impeller Fractured at Collahuasi Mine
    (2016) Ramos Moore, Esteban; Rosenkranz, Andreas
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    Influence of ex-situ annealing on the friction and wear performance of multi-layer Ti3C2Tx coatings
    (2024) Boidi, Guido; Zambrano, Dario; Broens, Martin I.; Moncada, Daniel; Varga, Markus; Ripoll, Manel Rodriguez; Badisch, Ewald; Escalona, Nestor; Gruetzmacher, Philipp G.; Gachot, Carsten; Rosenkranz, Andreas
    2D materials have gained momentum for lubrication purposes, which holds specifically true under more severe conditions such as elevated temperatures. Among them, MXenes are a new family of 2D materials, which offer an excellent electrical conductivity, tunable surface functionality, and outstanding mechanical properties. In the past five years, MXenes have been significantly studied for tribological applications due to their ability to form easy-to-shear tribofilms with excellent wear resistance. However, little is known regarding MXenes' tribological performance at elevated temperatures. Therefore, we systematically studied the tribological performance of spray-coated Ti3C2Tx coatings after thermal annealing at temperatures between 50 and 400 degrees C using linear-reciprocating ball-on-disc tribometry. Advanced materials characterization demonstrated that thermal annealing of MXenes results in the release of superficial and intercalated water, the removal of surface terminations, and the oxidation of Ti3C2Tx to TiO2. Consequently, the tribological performance of the annealed coatings deteriorated, which is particularly pronounced for thin coatings, high normal loads, and elevated annealing temperatures. Our results provide insight into the thermal stability of Ti3C2Tx coatings as well as the implications on their tribological performance.
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    Laser Interference Patterning of Steel Surfaces - Influence on the Frictional Performance under Dry and Lubricated Sliding Conditions
    (2016) Rosenkranz, Andreas; Gachot, Carsten; Ramos Moore, Esteban; Mucklich, Frank
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    Layered 2D Nanomaterials to Tailor Friction and Wear in Machine Elements—A Review
    (2022) Marian, Max; Berman, Diana; Rota, Alberto; Jackson, Robert L.; Rosenkranz, Andreas
    Recent advances in 2D nanomaterials, such as graphene, transition metal dichalcogenides, boron nitride, MXenes, allow not only to discover several new nanoscale phenomena but also to address the scientific and industrial challenges associated with the design of systems with desired physical properties. One of the great challenges for mechanical systems is associated with addressing friction and wear problems in machine elements. In this review, the beneficial properties of layered 2D materials that enable the control of their tribological behavior and make them excellent candidates for efficient friction and wear reduction in dry-running and boundary lubricated machine components are summarized. The recent studies highlighting the successful implementation of 2D structures when used as solid lubricant coatings or reinforcement phases in composites for various machine components including sliding and rolling bearings, gears, and seals are overviewed. The examples presented in the studies demonstrate the great potential for 2D materials to address the energy-saving needs by friction and wear reduction.
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    Mechanical and Bio-tribological Behavior of Ti3C2Tx-Reinforced CoCrMo Composites Fabricated by Additive Manufacturing
    (2025) Ramteke, Sangharatna M.; Ramos Grez, Jorge; Zambrano, Dario F.; Rosenkranz, Andreas; Marian, Max
    This study presents the bio-tribological analysis of Ti3C2Tx-reinforced CoCrMo matrix composites fabricated by laser beam powder bed fusion. Raman spectroscopy confirmed the structural and functional integrity during metal matrix composite (MMC) fabrication, while Vickers hardness increased with Ti3C2Tx content. Together with roughness and wettability, Ti3C2Tx-reinforced CoCrMo composites create a favorable balance between hardness, surface roughness, and hydrophilicity, making them suitable for biomedical applications. Bio-tribological analyses under dry and substitute synovial body fluid (SBF)-lubricated conditions revealed a substantial wear reduction of 78 and 39% compared to reference. These findings underscore Ti3C2Tx' ability to mitigate wear through enhanced interfacial interactions and lubrication, promising advancements in biomedical implants.