Nanomaterials

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26 pages, 15177 KiB

Open AccessArticle

Mechanical and Electrical Properties of Polyethylene Terephthalate Glycol/Antimony Tin Oxide Nanocomposites in Material Extrusion 3D Printing

by Markos Petousis, Nikolaos Michailidis, Vassilis Saltas, Vassilis Papadakis, Mariza Spiridaki, Nikolaos Mountakis, Apostolos Argyros, John Valsamos, Nektarios K. Nasikas and Nectarios Vidakis

Nanomaterials 2024, 14(9), 761; https://doi.org/10.3390/nano14090761 - 26 Apr 2024

Viewed by 948

Abstract

In this study, poly (ethylene terephthalate) (PETG) was combined with Antimony-doped Tin Oxide (ATO) to create five different composites (2.0–10.0 wt.% ATO). The PETG/ATO filaments were extruded and supplied to a material extrusion (MEX) 3D printer to fabricate the specimens following international standards. [...] Read more.

In this study, poly (ethylene terephthalate) (PETG) was combined with Antimony-doped Tin Oxide (ATO) to create five different composites (2.0–10.0 wt.% ATO). The PETG/ATO filaments were extruded and supplied to a material extrusion (MEX) 3D printer to fabricate the specimens following international standards. Various tests were conducted on thermal, rheological, mechanical, and morphological properties. The mechanical performance of the prepared nanocomposites was evaluated using flexural, tensile, microhardness, and Charpy impact tests. The dielectric and electrical properties of the prepared composites were evaluated over a broad frequency range. The dimensional accuracy and porosity of the 3D printed structure were assessed using micro-computed tomography. Other investigations include scanning electron microscopy and energy-dispersive X-ray spectroscopy, which were performed to investigate the structures and morphologies of the samples. The PETG/6.0 wt.% ATO composite presented the highest mechanical performance (21% increase over the pure polymer in tensile strength). The results show the potential of such nanocomposites when enhanced mechanical performance is required in MEX 3D printing applications, in which PETG is the most commonly used polymer. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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11 pages, 5384 KiB

Open AccessArticle

Embrittlement Mechanisms of HR3C Pipe Steel at Room Temperature in Ultra-Supercritical Unit

by Xinying Liu, Xue Cao and Zhongwu Zhang

Nanomaterials 2024, 14(3), 306; https://doi.org/10.3390/nano14030306 - 2 Feb 2024

Viewed by 649

Abstract

HR3C steel is an austenitic high-temperature-resistant steel. Because of its good strength and high-temperature performance, it has been widely used in ultra-supercritical power plant boilers. With the increasingly frequent start-up and shutdown of thermal power units, leakages of HR3C steel pipes have occasionally [...] Read more.

HR3C steel is an austenitic high-temperature-resistant steel. Because of its good strength and high-temperature performance, it has been widely used in ultra-supercritical power plant boilers. With the increasingly frequent start-up and shutdown of thermal power units, leakages of HR3C steel pipes have occasionally occurred due to the embrittlement of HR3C pipe steel after a long service duration. In this study, the embrittlement mechanisms of HR3C pipe steel are investigated systematically. The mechanical properties of the pipe steel after running for 70,000 h in an ultra-supercritical unit were determined. As a comparison, the pipe steel supplied in the same batch was aged at 700 degrees Celsius for 500 h. The mechanical properties and the micro-precipitation of the aged counterparts were also determined for comparison. The results show that the embrittlement of HR3C pipe steel in service for 70,000 h is obvious. The average impact absorption is only 5.5 J, which is a decrease of 96.7%. It is found that embrittlement of HR3C steel also occurs after 500 h of aging at 700 °C, and the average value of impact absorption energy decreases by 70.4%. The comparison experiment between the in-service pipe steel and the aged pipe steel shows that in the rapid decline stage of the impact toughness of HR3C steel, the M₂₃C₆ carbide in the microstructure has a continuous chain distribution in the grain boundary. There were no other precipitated phases observed. The rapid precipitation and aggregation of M₂₃C₆ carbides leads to the initial embrittlement of HR3C steel at room temperature. The CRFe-type σ phase was found in the transmission electron microscope (TEM) image of the steel pipe after 70 thousand hours of use. The precipitation of the σ phase further induces the embrittlement of HR3C pipe steel after a long service duration. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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14 pages, 3193 KiB

Open AccessArticle

Spatial Topological Structure Design of Porous Ti–6Al–4V Alloy with Low Modulus and Magnetic Susceptibility

by Qian Li, Qiang Li, Shasha Lu and Deng Pan

Nanomaterials 2023, 13(24), 3113; https://doi.org/10.3390/nano13243113 - 11 Dec 2023

Viewed by 766

Abstract

Ti–6Al–4V alloy is widely used as a biomaterial for hard tissue replacement, but its Young’s modulus is still higher than that of human bone tissue, which may cause a “stress shielding” effect and lead to implant loosening. In addition, metal implants with low [...] Read more.

Ti–6Al–4V alloy is widely used as a biomaterial for hard tissue replacement, but its Young’s modulus is still higher than that of human bone tissue, which may cause a “stress shielding” effect and lead to implant loosening. In addition, metal implants with low magnetic susceptibility are beneficial for obtaining minimal artifacts in magnetic resonance imaging. To reduce Young’s modulus and magnetic susceptibility of Ti–6Al–4V alloy, a series of irregular prismatic porous structure models were designed based on the Voronoi principle, built by changing the irregularity, prism-diameter-to-initial-seed-spacing ratio, and seed number, and studied using finite-element analysis. Porous samples were prepared by selective laser melting and subjected to a compression test and magnetic susceptibility test. The simulation results show that the prism-diameter-to-initial-seed-spacing ratio has the greatest impact on porosity compared with the irregularity and seed number. The simulation-predicted porosity and compression modulus are highly consistent with the measured ones. The irregular prismatic porous Ti–6Al–4V samples exhibit mechanical properties similar to those of human bones and show a magnetic susceptibility of no more than 50% that of compact Ti–6Al–4V. A regulatable irregular prismatic porous structure is feasible for designing porous implants with desirable properties for biomedical applications. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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10 pages, 3599 KiB

Open AccessArticle

Systematically Study the Tensile and Compressive Behaviors of Diamond-like Carbon

by Jingxiang Xu, Yina Geng, Zhenhua Chu, Qingsong Hu, Yanhua Lei and Yang Wang

Nanomaterials 2023, 13(11), 1772; https://doi.org/10.3390/nano13111772 - 31 May 2023

Cited by 2 | Viewed by 939

Abstract

It is important to understand the mechanical properties of diamond-like carbon (DLC) for use not only in frictionand wear-resistant coatings, but also in vibration reduction and damping increase at the layer interfaces. However, the mechanical properties of DLC are influenced by the working [...] Read more.

It is important to understand the mechanical properties of diamond-like carbon (DLC) for use not only in frictionand wear-resistant coatings, but also in vibration reduction and damping increase at the layer interfaces. However, the mechanical properties of DLC are influenced by the working temperature and its density, and the applications of DLC as coatings are limited. In this work, we systematically studied the deformation behaviors of DLC under different temperatures and densities using compression and tensile testing of DLC by molecular dynamics (MD) methods. In our simulation results, the values of tensile stress and compressive stress decreased and tensile strain and compressive strain increased as the temperature increased from 300 K to 900 K during both tensile and compressive processes, indicating that the tensile stress and tensile strain depend on the temperature. During the tensile simulation, Young’s modulus of DLC models with different densities had a different sensitivity to the increase in temperature, and the DLC model with a high density was more sensitive than that with a low density, which was not seen in the compression process. We conclude that the Csp3-Csp2 transition leads to tensile deformation, while the Csp2-Csp3 transition and relative slip dominate compressive deformation. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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13 pages, 3976 KiB

Open AccessArticle

High-Performance On-Chip Racetrack Resonator Based on GSST-Slot for In-Memory Computing

by Honghui Zhu, Yegang Lu and Linying Cai

Nanomaterials 2023, 13(5), 837; https://doi.org/10.3390/nano13050837 - 23 Feb 2023

Cited by 6 | Viewed by 1466

Abstract

The data shuttling between computing and memory dominates the power consumption and time delay in electronic computing systems due to the bottleneck of the von Neumann architecture. To increase computational efficiency and reduce power consumption, photonic in-memory computing architecture based on phase change [...] Read more.

The data shuttling between computing and memory dominates the power consumption and time delay in electronic computing systems due to the bottleneck of the von Neumann architecture. To increase computational efficiency and reduce power consumption, photonic in-memory computing architecture based on phase change material (PCM) is attracting increasing attention. However, the extinction ratio and insertion loss of the PCM-based photonic computing unit are imperative to be improved before its application in a large-scale optical computing network. Here, we propose a 1 × 2 racetrack resonator based on Ge₂Sb₂Se₄Te₁ (GSST)-slot for in-memory computing. It demonstrates high extinction ratios of 30.22 dB and 29.64 dB at the through port and drop port, respectively. The insertion loss is as low as around 0.16 dB at the drop port in the amorphous state and about 0.93 dB at the through port in the crystalline state. A high extinction ratio means a wider range of transmittance variation, resulting in more multilevel levels. During the transition between crystalline and amorphous states, the tuning range of the resonant wavelength is as high as 7.13 nm, which plays an important role in the realization of reconfigurable photonic integrated circuits. The proposed phase-change cell demonstrates scalar multiplication operations with high accuracy and energy efficiency due to a higher extinction ratio and lower insertion loss compared with other traditional optical computing devices. The recognition accuracy on the MNIST dataset is as high as 94.6% in the photonic neuromorphic network. The computational energy efficiency can reach 28 TOPS/W, and the computational density of 600 TOPS/mm². The superior performance is ascribed to the enhanced interaction between light and matter by filling the slot with GSST. Such a device enables an effective approach to power-efficient in-memory computing. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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9 pages, 18418 KiB

Open AccessArticle

Long-Term Operational Stability of Ta/Pt Thin-Film Microheaters: Impact of the Ta Adhesion Layer

by Ivan A. Kalinin, Ilya V. Roslyakov, Dmitry N. Khmelenin and Kirill S. Napolskii

Nanomaterials 2023, 13(1), 94; https://doi.org/10.3390/nano13010094 - 25 Dec 2022

Cited by 4 | Viewed by 2547

Abstract

Microheaters with long-term stability are crucial for the development of a variety of microelectronic devices operated at high temperatures. Structured Ta/Pt bilayers, in which the Ta sublayer ensures high adhesion of the Pt resistive layer, are widely used to create microheaters. Herein, a [...] Read more.

Microheaters with long-term stability are crucial for the development of a variety of microelectronic devices operated at high temperatures. Structured Ta/Pt bilayers, in which the Ta sublayer ensures high adhesion of the Pt resistive layer, are widely used to create microheaters. Herein, a comprehensive study of the microstructure of Ta/Pt films using high-resolution transmission electron microscopy with local elemental analysis reveals the twofold nature of Ta after annealing. The main fraction of Ta persists in the form of tantalum oxide between the Pt resistive layer and the alumina substrate. Such a sublayer hampers Pt recrystallization and grain growth in bilayered Ta/Pt films in comparison with pure Pt films. Tantalum is also observed inside the Pt grains as individual Ta nanoparticles, but their volume fraction is only about 2%. Microheaters based on the 10 nm Ta/90 nm Pt bilayers after pre-annealing exhibit long-term stability with low resistance drift at 500 °C (less than 3%/month). Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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15 pages, 818 KiB

Open AccessArticle

Anisotropic Thermal Conductivity of Inkjet-Printed 2D Crystal Films: Role of the Microstructure and Interfaces

by Mizanur Rahman, Khaled Parvez, Giorgia Fugallo, Chaochao Dun, Oliver Read, Adriana Alieva, Jeffrey J. Urban, Michele Lazzeri, Cinzia Casiraghi and Simone Pisana

Nanomaterials 2022, 12(21), 3861; https://doi.org/10.3390/nano12213861 - 1 Nov 2022

Cited by 3 | Viewed by 2140

Abstract

Two-dimensional (2D) materials are uniquely suited for highly anisotropic thermal transport, which is important in thermoelectrics, thermal barrier coatings, and heat spreaders. Solution-processed 2D materials are attractive for simple, low-cost, and large-scale fabrication of devices on, virtually, any substrate. However, to date, there [...] Read more.

Two-dimensional (2D) materials are uniquely suited for highly anisotropic thermal transport, which is important in thermoelectrics, thermal barrier coatings, and heat spreaders. Solution-processed 2D materials are attractive for simple, low-cost, and large-scale fabrication of devices on, virtually, any substrate. However, to date, there are only few reports with contrasting results on the thermal conductivity of graphene films, while thermal transport has been hardly measured for other types of solution-processed 2D material films. In this work, inkjet-printed graphene, h-BN and MoS

_{2}

films are demonstrated with thermal conductivities of ∼10 Wm

^{- 1}

K

^{- 1}

and ∼0.3 Wm

^{- 1}

K

^{- 1}

along and across the basal plane, respectively, giving rise to an anisotropy of ∼30, hardly dependent on the material type and annealing treatment. First-principles calculations indicate that portion of the phonon spectrum is cut-off by the quality of the thermal contact for transport along the plane, yet the ultra-low conductivity across the plane is associated with high-transmissivity interfaces. These findings can drive the design of highly anisotropic 2D material films for heat management applications. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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Review

Jump to: Research

23 pages, 5637 KiB

Open AccessReview

A Comprehensive Review on Printed Electronics: A Technology Drift towards a Sustainable Future

by Sridhar Chandrasekaran, Arunkumar Jayakumar and Rajkumar Velu

Nanomaterials 2022, 12(23), 4251; https://doi.org/10.3390/nano12234251 - 29 Nov 2022

Cited by 3 | Viewed by 2970

Abstract

Printable electronics is emerging as one of the fast-growing engineering fields with a higher degree of customization and reliability. Ironically, sustainable printing technology is essential because of the minimal waste to the environment. To move forward, we need to harness the fabrication technology [...] Read more.

Printable electronics is emerging as one of the fast-growing engineering fields with a higher degree of customization and reliability. Ironically, sustainable printing technology is essential because of the minimal waste to the environment. To move forward, we need to harness the fabrication technology with the potential to support traditional process. In this review, we have systematically discussed in detail the various manufacturing materials and processing technologies. The selection criteria for the assessment are conducted systematically on the manuscript published in the last 10 years (2012–2022) in peer-reviewed journals. We have discussed the various kinds of printable ink which are used for fabrication based on nanoparticles, nanosheets, nanowires, molecular formulation, and resin. The printing methods and technologies used for printing for each technology are also reviewed in detail. Despite the major development in printing technology some critical challenges needed to be addressed and critically assessed. One such challenge is the coffee ring effect, the possible methods to reduce the effect on modulating the ink environmental condition are also indicated. Finally, a summary of printable electronics for various applications across the diverse industrial manufacturing sector is presented. Full article

(This article belongs to the Special Issue Nano-Scale Microstructure Evolution, Micromechanics Behavior and Surface Control in Additive Manufacturing)

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