Figure 5 - uploaded by Santanu Das
Content may be subject to copyright.
Lateral force vs. displacement curve of nano-scratch study; (b) variation of friction coefficient on the top surface of the PtMG film; (c and d) The SPM image and the 3D optical interferometer image of the nano-scratch on the surface of the PtMG thin film.
Source publication
Noble-metal-based amorphous alloys show exceptional electrocatalytic activity and durability, and are promising for next generation electrochemical devices for energy conversion and storage. Here, we report on the electro-mechanical behavior of pulsed laser deposited Pt-based metallic glass thin film of composition Pt57.5Cu14.7Ni5.3P22.5. Pulsed la...
Contexts in source publication
Context 1
... as well as the optical interferometer image (Fig. 4d), which indicates unusually high ductility for this metallic glass. In addition to the high surface hardness and large modulus, the enhanced ductility shows remarkable load-bearing ability at the small scales. The lateral force and friction coefficient as a function of displacement are shown in Fig. 5a and b, respectively. The friction coefficient is low, indicating good lubrication characteristics. The load increases continuously, with the film delaminating at a normal load of around 120 mN. This The scratch is uniform and the strong bond with the substrate is clearly seen from the SPM and optical interferometer images ( Fig. 5c and ...
Context 2
... are shown in Fig. 5a and b, respectively. The friction coefficient is low, indicating good lubrication characteristics. The load increases continuously, with the film delaminating at a normal load of around 120 mN. This The scratch is uniform and the strong bond with the substrate is clearly seen from the SPM and optical interferometer images ( Fig. 5c and ...
Citations
... Das et al. [60] ont étudié par NIE le comportement électromécanique d'un film mince de verre métallique déposé par ablation laser pulsé (PLD pour « Pulsed Laser Deposition ») sur un substrat de silicium, d'épaisseur 300 nm et de composition Pt57,5Cu14,7Ni5,3P22,5. La figure I.24.a montre la courbe de charge obtenue avec un indenteur Berkovich en diamant et la figure I.24.b présente la courbe de courant en fonction de la profondeur d'indentation. Sur la courbe de charge, des pop-in attribués au développement de bandes de cisaillement sont observés. ...
Cette thèse s’inscrit dans le cadre du développement de matériaux innovants pour des applications multifonctionnelles (en micro/nanotechnologies, en métallurgie, …). En effet, les cahiers des charges « Matériaux » de ces développements exigent de plus en plus de combiner diverses propriétés (mécaniques, électriques, diélectriques, …) qui sont parfois antinomiques, le tout à des échelles submicroniques. La caractérisation de ces matériaux nécessite donc des techniques adaptées à ces contraintes. Le travail effectué pendant cette thèse repose sur le développement, l’amélioration et l’application d’une technique de caractérisation multifonctionnelle innovante : la nanoindentation couplée aux mesures électriques et intégrée dans un MEB. Le dispositif utilisé a été développé au laboratoire SIMaP. Cet instrument est un nanoindenteur, initialement dédié à des essais mécaniques, qui a été fonctionnalisé afin de réaliser simultanément des mesures électriques. De plus, le dispositif peut être intégré dans un MEB afin d’assurer le positionnement de l’indenteur avec une résolution de l’ordre de la centaine de nanomètres, ainsi que pour visualiser des événements physiques en temps réel. Le but de ce travail est d’appliquer cette technique novatrice à trois systèmes ayant des intérêts industriels afin d’étudier leurs propriétés électriques et mécaniques locales. Le premier matériau est un alliage métallique multiphasé composé d’argent, de cuivre et de palladium (AgPdCu). Grâce aux mesures électriques associées aux essais de nanoindentation, une méthodologie complète a été développée (en s’appuyant en particulier sur les caractéristiques courant-tension du contact) afin de suivre en continu l’évolution de l’aire de contact au cours de l’enfoncement de la pointe. En outre, la visée au MEB a permis de positionner l’indenteur au centre des phases dont la taille est micrométrique, s’affranchissant ainsi d’essais statistiques chronophages. Ainsi, le module élastique et la dureté des phases individuelles ont été déterminés. Le deuxième système étudié est une structure piézoélectrique constituée d’îlots de nitrure d’aluminium (AlN) sur des piliers de silicium. Le coefficient piézoélectrique efficace a été mesuré avec un poinçon plat induisant une réponse mécanique parfaitement élastique du système. Ce dernier est en accord avec les valeurs retrouvées dans la littérature, ce qui montre l’efficacité de la nanoindentation électrique in situ MEB pour ce type de mesures. Le même matériau a été indenté avec une pointe Berkovich induisant de la plasticité. La réponse piézoélectrique est différente de la précédente certainement à cause des défauts structuraux injectés dans le matériau. Le troisième système est quant à lui un empilement de couches minces incluant un film de nitrure de silicium (Si3N4) déposé sur une couche métallique (AlSiCu). Les courants de fuite à travers le diélectrique ont été mesurés et corrélés à la dégradation mécanique. L’intégration du dispositif dans le MEB a permis de visualiser la fissuration du film en temps réel. L’effet d’une sous-couche fragile ou ductile sur la réponse mécanique du système a également été étudié avec l’appui de simulations numériques menées par la méthode des éléments finis (FEM). Les résultats montrent qu’en présence d’une sous-couche ductile, le mécanisme prédominant est la fissuration du film fragile, alors qu’en son absence, le mécanisme prédominant est la plastification du film fragile. Finalement, la technique de nanoindentation électrique in situ MEB est un outil parfaitement adapté pour réaliser des mesures électriques et mécaniques locales de haute sensibilité à des échelles submicroniques. Grâce au présent travail, cette technique peut être ouverte à la caractérisation de systèmes dont les propriétés électriques dépendent de stimuli mécaniques, et réciproquement.
... PLD is a flexible process as several types of materials can be deposited, and any material can be used as a substrate. Also, it enables microstructure ranging from crystalline to entirely amorphous [34]. Furthermore, PLD can be employed to grow complex compositions by congruent vaporisation, ensuring that the film grown replicates the same composition as that of the target. ...
... Furthermore, PLD can be employed to grow complex compositions by congruent vaporisation, ensuring that the film grown replicates the same composition as that of the target. This process is predominantly appropriate for noble metal-based amorphous coatings comprising metalloids like boron, which are challenging to coat by other thin film coating or deposition processes [34,35]. ...
Amorphous thin film metallic glasses (TFMGs) have given rise to a widespread research interest due to their technological promise for practical applications and scientific importance in the biomedical field. As a result of their disordered atomic structure (leading to amorphicity), these TFMGs symbolize a new class of structural and functional materials with extraordinary properties, including exciting strength along with superior mechanical properties and biological properties. TFMG top-coats have the potential to improve the strength, corrosion resistance, biocompatibility, and life span of potential biomaterials (metallic, ceramics, or polymers). This article reviews the mechanical properties and biological behavior of TFMGs as well as the current progress in Zr-based, Ti-based, Fe-based, and Mg-based TFMGs for biomedical applications.
... 33 Existing examples were Pd-based TFMG that has been used as a sensing film in a capacitive MEMS hydrogen sensor 34 and laser ablated Pt 57.5 Cu 14.7 Ni 5.3 P 22.5 that was a potential electrode material. 35 ...
In this article, we provide a perspective overview of the iconic properties, recent application-oriented research, and future commercialization opportunities of thin film metallic glasses (TFMGs). A brief review on the preparation and fundamental properties of TFMGs will be given first. TFMGs possess attractive properties such as corrosion resistance, extremely low roughness, and antibacterial characteristics, which give rise to various applications in biomedical devices, sensors, and tribology. Therefore, a number of our representative works will be reviewed to showcase the benefits of TFMGs over traditional materials and processing in these applications. In addition, new perspectives in the research and development of TFMGs and opportunities for commercialization will also be highlighted.
... Change and variation of the lateral force have been observed in the lateral forcedisplacement curve for all films prepared at sputtering currents of 0.1 A, 0.2 A and 0.3 A in Fig. 12 (b). This significant variation in lateral force indicates that strong bonding exists in all films [45]. Curves of the coefficient of friction versus the lateral displacement are illustrated for films in 2000 µN in Fig. 12(c). ...
Fe–Cr–Mo–Co–C–B–Si thin film metallic glasses were prepared through DC magnetron sputtering under different sputtering currents. Microstructural studies of the thin films were carried out using GIXRD, FE-SEM, AFM and TEM techniques. Nanoscratch, nanoindentation and fracture toughness were used for investigation of mechanical properties. Corrosion behaviors were evaluated by polarization potentiodynamic, potentiostatic and impedance tests. A broad hump was observed from GIXRD pattern showing formation of the amorphous structure and full glassy phase was confirmed by the SAED pattern. The deposition at different sputtering currents affected on the microstructure properties such as surface morphology, topography and cross-sectional growth of TFMGs. Increase the sputtering current led to an increase in surface roughness, nanohardness, Young's modulus, fracture toughness and pile-up value of TFMG as well as coefficient of friction and elastic recovery of TFMG decreased. The TFMG prepared at sputtering current of 0.3 A exhibited an excellent corrosion resistance along with good mechanical properties.
... Noble-metal-based metallic glasses, on the other hand, display phenomenal electrocatalytic activity and durability, making them promising candidate materials for next-generation energy storage and conversion devices. 61,175,176 Their disordered atomic configuration result in a complex electronic structure that contribute to enhanced catalytic properties. For this reason, the research interest in investigating BMGs, as high-performance catalysts, is swiftly mounting. ...
Bulk metallic glasses (BMGs), that display extraordinary properties of high strength, corrosion resistance, polymer-like formability, and excellent magnetic properties, are emerging as modern quintessential engineering materials. BMGs have garnered significant research enthusiasm owing to their tremendous technological and scientific standing. In this article, the recent advancements in the field of BMGs and their applications are put in a nutshell. Novel state-of-the-art production routes and nano/microimprinting strategies with salient features capable of circumventing the processing related complexities as well as accelerating modern developments, are briefly summarized. Heterogeneous BMG composite systems that lead to incredible combination of otherwise conflicting properties are highlighted. Biocorrosion studies and recent developments in the field of magnetic BMGs are presented owing to their significance for prospective biomedical and magnetic applications, respectively. In the last section, the current status of BMGs applications in the field of catalysis, biomedical materials, structural materials, functional materials, microelectromechanical systems (MEMS), and micro/ macro devices are summed up.
... 5,6 The nano-ECR technique has already been successfully employed to study pressure-induced phase transformations in Si 7 and GeSb 2 Te 4 , 8 and to study the electromechanical responses of cellular carbon nanotube structures. 9 Although it has been previously applied to MGs, 10,11 the relationship between the plastic deformation and the current output has not been fully understood. This is because, while the mechanical tests conducted in the elastic regime of MGs might trigger only minor inelastic atomic shuffling, 11 plastic deformation comprises of multiple processes, all of which can potentially alter the contact resistance. ...
Simultaneous measurement of the electrical contact resistance (ECR) during nanoindentation of a Pd-based bulk metallic glass(BMG) shows discontinuities in the current during the loading segment. Through an analysis of the effective change in the contact area that occurs due to the plastic flow via shear banding, we show that the current surges, which are synchronous with the displacement bursts, are associated with shear band nucleation and/or propagation. The potential of nano-ECR measurements for monitoring plastic events in BMGs is discussed.
Recently, thin film metallic glasses (TFMGs) gained renewed attention as they can circumvent the brittleness problem of bulk metallic glasses. When sputtered from a multicomponent cast target, the composition control of TFMG is always challenging. Here, we demonstrate a tight composition control of sputtered Ti-Zr-Cu-Ni-Al TFMG by a spark plasma sintered multicomponent target and investigated their structural and nanoscratch properties. The radio frequency (RF) power and Ar pressure were tuned to optimize nanoscratch properties. The highest hardness (~16.2 GPa) and thus best nanoscratch resistance was obtained at an RF power of 160 W and Ar pressure of 7 Pa. The best nanoscratch properties originated from the dense, fine column morphology of the TFMG. Moreover, it was found that the scratch mechanism changed from plowing to a combination of plowing and stick-slip under a ramping scratching load of 10 mN. The transition happened progressively at lower loads when the hardness of the TFMG decreased. This study provides a useful guideline for developing TFMG as a scratch-resistant protective coating.
Electronic materials such as semiconductors, piezo‐ and ferroelectrics, and metal oxides are primary constituents in sensing, actuation, nanoelectronics, memory, and energy systems. Although significant progress is evident in understanding the mechanical and electrical properties independently using conventional techniques, simultaneous and quantitative electromechanical characterization at the nanoscale using in situ techniques is scarce. It is essential because coupling/linking electrical signal to the nanoscale plasticity provides vital information regarding the real‐time electromechanical behavior of materials, which is crucial for developing miniaturized smarter technologies. With the advent of conductive nanoindentation, researchers have been able to get valuable insights into the nanoscale plasticity (otherwise not possible by conventional means) in a wide variety of bulk and small‐volume materials, quantify the electromechanical properties, understand the dielectric breakdown phenomenon and the nature of electrical contacts in thin films, etc., by continuously monitoring the real‐time electrical signal changes during any point on the indentation load–hold–unload cycle. This comprehensive Review covers probing the electromechanical behavior of materials using in situ conductive nanoindentation, data analysis methods, the validity of the models and limitations, and electronic conduction mechanisms at the nanocontacts, quantification of resistive components, applications, progress, and existing issues, and provides a futuristic outlook.
The aim of our study is to investigate the effect of boron with different ratios in Ti-Cu-Pd-Zr metallic glass (MG) matrix (Ti-Cu-Pd-Zr:B) fabricated by Pulsed Laser Deposition (PLD) for biomedical implants. The Ti based Thin Film Metallic Glasses (TFMGs) in combination with boron (in different atomic %) was assessed in attaining the combined properties, like outstanding corrosion resistant properties and good biocompatibility in this work. The disordered structure and amorphous nature of the Ti-Cu-Pd-Zr:B thin films systems were achieved by the PLD process and affirmed by XRD and transmission electron microscopy. The boron incorporation in the TFMG has been elucidated by XPS analysis. The boron containing films displays distribution of boron protuberances interleaved in the amorphous matrix was stated from SEM analysis. It is found that increase in atomic percentage of boron contents in TFMG results in the improvement in glass transition temperatures. The electrochemical parameters suggest better corrosion resistance and capabilities of passivity when boron percentage was increased in the film thereby preventing adverse biological reactions. TFMGs exhibited excellent hemocompatibility by preventing the platelet activation. MTT assay manifests increase in cell concentration with culture period on the TFMGs for the MC3T3‐E1 preosteoblasts cells. Cell morphology was also studied which confirmed the viable state of the cells on the TFMG surfaces. The combination of such distinctive properties marks these TFMG systems as prospective aspirants for biomedical implants.
