Synthesis and Mechanical Characterization of Aligned Carbon Nanotube Metal- and Carbon-matrix Nanocomposites PDF Download
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Author: Amy Ruth Vanderhout
Publisher:
ISBN:
Category :
Languages : en
Pages : 224
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Book Description
Carbon nanotube (CNT) assemblies are seeing increasing use in engineering applications due to their advantaged, mass-specific physical properties. The high strength-to-weight ratio, electrical and thermal conductivity, and elastic properties make CNTs ideal for many aerospace, automotive, and electrical applications. In structural materials, CNTs are an outstanding candidate to provide nano-reinforcement, both in hybrid composites and nanocomposites, and they have been found to improve the hardness, yield strength, and conductivity of their matrix material. Additional enhancement of these matrices can be realized by using aligned CNTs (A-CNTs) of increased volume fraction, as explored in this work. In this thesis, ceramic matrix nanocomposites (CMNCs), specifically A-CNT/carbon matrix nanocomposites (A/C-NCs), are synthesized by first infusing a carbon precursor resin into A-CNT arrays with CNT volume fractions (v[subscript f]) ranging from 1-30 vol%, and then pyrolyzing the resin to create a carbon matrix around the A-CNTs. Previous work with A/C-NC hardness suggests that such a lightweight, superhard material may rival the density-normalized hardness of diamond at high v[subscript f]. Various processes were refined and tested in this work, yielding microscale void-free A/CNCs up to 30% v[subscript f], with an ~7% improvement in hardness over baseline pyrolytic carbon (PyC) for 1% v[subscript f] A/C-NCs and ∼10% improvement in hardness for 5% v[subscript f] A-CNTs. A reinfusion (i.e. an initial infusion/pyrolysis cycle with three additional reinfusion/pyrolysis cycles) procedure was developed and implemented, and testing is recommended as immediate future work. Although hardness determination of these reinfused samples is left for future work, the X-ray CT images of the final A/C-NCs after the fourth infusion show excellent infusion and few voids, suggesting that high hardness will be achieved. This thesis also explores and develops synthesis techniques for metal matrix nanocomposites (MMNCs), focusing on an aluminum matrix. As the surface energy of ACNTs is not conducive to wetting by Al (and many other metals), this surface energy must first be altered to allow Al matrix infusion for consistent composite fabrication. TiO2 is conformally decorated onto ~100 [mu]m-tall A-CNT arrays via atomic layer deposition (ALD). A reduction process for the TiO2 coating was developed, and a reduction to TiH2 was determined to be promising, as the TiH2 will not oxidize prior to Al infusion but can easily be reduced in a vacuum oven apparatus designed specifically to meet the needs of Al infusion. Towards MMNCs, both solder and aluminum matrices are infused into the TiO2-decorated A-CNTs. The solder experiments yielded mixed success, as the results suggest that both the reduction and the vacuum infusion steps are important factors determining successful wetting. Although Al infusion into an A-CNT array was unsuccessful without a dedicated Al infusion apparatus, molten Al was found to wet Ti well, which suggests that the Ti coating may allow for successful A-CNT wetting. Additional recommendations are provided to further refine the A/Al-NC fabrication process to improve Al infusion.
Author: Amy Ruth Vanderhout
Publisher:
ISBN:
Category :
Languages : en
Pages : 224
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Book Description
Carbon nanotube (CNT) assemblies are seeing increasing use in engineering applications due to their advantaged, mass-specific physical properties. The high strength-to-weight ratio, electrical and thermal conductivity, and elastic properties make CNTs ideal for many aerospace, automotive, and electrical applications. In structural materials, CNTs are an outstanding candidate to provide nano-reinforcement, both in hybrid composites and nanocomposites, and they have been found to improve the hardness, yield strength, and conductivity of their matrix material. Additional enhancement of these matrices can be realized by using aligned CNTs (A-CNTs) of increased volume fraction, as explored in this work. In this thesis, ceramic matrix nanocomposites (CMNCs), specifically A-CNT/carbon matrix nanocomposites (A/C-NCs), are synthesized by first infusing a carbon precursor resin into A-CNT arrays with CNT volume fractions (v[subscript f]) ranging from 1-30 vol%, and then pyrolyzing the resin to create a carbon matrix around the A-CNTs. Previous work with A/C-NC hardness suggests that such a lightweight, superhard material may rival the density-normalized hardness of diamond at high v[subscript f]. Various processes were refined and tested in this work, yielding microscale void-free A/CNCs up to 30% v[subscript f], with an ~7% improvement in hardness over baseline pyrolytic carbon (PyC) for 1% v[subscript f] A/C-NCs and ∼10% improvement in hardness for 5% v[subscript f] A-CNTs. A reinfusion (i.e. an initial infusion/pyrolysis cycle with three additional reinfusion/pyrolysis cycles) procedure was developed and implemented, and testing is recommended as immediate future work. Although hardness determination of these reinfused samples is left for future work, the X-ray CT images of the final A/C-NCs after the fourth infusion show excellent infusion and few voids, suggesting that high hardness will be achieved. This thesis also explores and develops synthesis techniques for metal matrix nanocomposites (MMNCs), focusing on an aluminum matrix. As the surface energy of ACNTs is not conducive to wetting by Al (and many other metals), this surface energy must first be altered to allow Al matrix infusion for consistent composite fabrication. TiO2 is conformally decorated onto ~100 [mu]m-tall A-CNT arrays via atomic layer deposition (ALD). A reduction process for the TiO2 coating was developed, and a reduction to TiH2 was determined to be promising, as the TiH2 will not oxidize prior to Al infusion but can easily be reduced in a vacuum oven apparatus designed specifically to meet the needs of Al infusion. Towards MMNCs, both solder and aluminum matrices are infused into the TiO2-decorated A-CNTs. The solder experiments yielded mixed success, as the results suggest that both the reduction and the vacuum infusion steps are important factors determining successful wetting. Although Al infusion into an A-CNT array was unsuccessful without a dedicated Al infusion apparatus, molten Al was found to wet Ti well, which suggests that the Ti coating may allow for successful A-CNT wetting. Additional recommendations are provided to further refine the A/Al-NC fabrication process to improve Al infusion.
Author: Itai Y. Stein
Publisher:
ISBN:
Category :
Languages : en
Pages : 141
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Book Description
Materials comprising carbon nanotube (CNT) aligned nanowire (NW) polymer nanocomposites (A-PNCs) have emerged as promising architectures for next-generation multifunctional applications. Enhanced operating regimes, such as operating temperatures, motivate the study of CNT aligned NW ceramic matrix nanocomposites (A-CMNCs). Here we report the synthesis of CNT A-CMNCs through the pyrolysis of CNT A-PNC precursors, creating carbon matrix CNT A-CMNCs. The CNT A-CMNC processing parameters were evaluated using an apparent density measurement, polymer re-infusion modeling, and CNT quality analysis, which elucidate the limitations of the processing parameters currently used to fabricate CNT A-CMNCs. Theoretical tools developed to help quantify and analyze the morphology of the CNTs in the A-CMNCs, and NWs in general, show that morphological parameters, such as NW outer diameter and inter-wire spacing, that are usually overlooked may have significant effects on the physical properties of NW architectures. Mechanical characterization of the CNT A-CMNCs illustrates that the presence of aligned CNTs can lead to an enhancement of > 60% in microhardness, meaning that the fabrication of high strength, high temperature, lightweight next-generation material architectures may be possible using the presented method. Finally, factors that influence the physical properties of CNT A-CMNCs, such as CNT waviness and the porosity of the carbon matrix, are identified, and since their effects cannot be modeled using existing theory, future paths of study that could enable their quantification are recommended.
Author: Moones Rahmandoust
Publisher: Springer
ISBN: 3319002511
Category : Technology & Engineering
Languages : en
Pages : 246
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Book Description
This volume presents the characterization methods involved with carbon nanotubes and carbon nanotube-based composites, with a more detailed look at computational mechanics approaches, namely the finite element method. Special emphasis is placed on studies that consider the extent to which imperfections in the structure of the nanomaterials affect their mechanical properties. These defects may include random distribution of fibers in the composite structure, as well as atom vacancies, perturbation and doping in the structure of individual carbon nanotubes.
Author: Andy Nieto
Publisher: CRC Press
ISBN: 1000377520
Category : Technology & Engineering
Languages : en
Pages : 390
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Book Description
This discovery of carbon nanotubes (CNT) three decades ago ushered in the technological era of nanotechnology. Among the most widely studied areas of CNT research is their use as structural reinforcements in composites. This book describes the development of CNT reinforced metal matrix composites (CNT-MMCs) over the last two decades. The field of CNT-MMCs is abundant in fundamental science, rich in engineering challenges and innovations and ripe for technological maturation and commercialization. The authors have sought to present the current state of the-art in CNT-MMC technology from their synthesis to their myriad potential end-use applications. Specifically, topics explored include: • Advantages, limitations, and evolution of processing techniques used to synthesize and fabricate CNT-MMCs • Emphasizes dispersion techniques of CNTs in metallic systems, a key challenge to the successful and widespread implementation of CNT-MMCs. Methods for quantification and improved control of CNT distributions are presented • Methods for quantification and improved control of CNT distributions are presented • Characterization techniques uniquely suited for charactering these nanoscale materials and their many chemical and physical interactions with the metal matrix, including real-time in-situ characterization of deformation mechanisms • Electron microscope images from premier studies enrich discussions on micro-mechanical modeling, interfacial design, mechanical behavior, and functional properties • A chapter is dedicated to the emergence of dual reinforcement composites that seek to enhance the efficacy of CNTs and lead to material properties by design This book highlights seminal findings in CNT-MMC research and includes several tables listing processing methods, associated CNT states, and resulting properties in order to aid the next generation of researchers in advancing the science and engineering of CNT-MMCs. In addition, a survey of the patent literature is presented in order to shed light on what the first wave of CNT-MMC commercialization may look like and the challenges that will have to be overcome, both technologically and commercially.
Author: Arvind Agarwal
Publisher: CRC Press
ISBN: 1439811504
Category : Technology & Engineering
Languages : en
Pages : 318
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Book Description
From the Foreword, written by legendary nano pioneer M. Meyyappan, Chief Scientist for Exploration Technology NASA Ames Research Center, Moffett Field, California, USA: "...there is critical need for a book to summarize the status of the field but more importantly to lay out the principles behind the technology. This is what Professor Arvind Agarwal and his co-workers ... have done here." Carbon Nanotubes: Reinforced Metal Matrix Composites reflects the authors’ desire to share the benefits of nanotechnology with the masses by developing metal matrix carbon nanotube (MM-CNT) composites for large-scale applications. Multiwall carbon nanotubes can now be produced on a large scale and at a significantly reduced cost. The book explores potential applications and applies the author’s own research to highlight critical developmental issues for different MM-CNT composites—and then outline novel solutions. With this problem-solving approach, the book explores: Advantages, limitations, and the evolution of processing techniques used for MM-CNT composites Characterization techniques unique to the study of MM-CNT composites—and the limitations of these methods Existing research on different MM-CNT composites, presented in useful tables that include composition, processing method, quality of CNT dispersion, and properties The micro-mechanical strengthening that results from adding CNT The applicability of micro-mechanics models in MM-CNT composites Significance of chemical stability for carbon nanotubes in the metal matrix as a function of processing, and its impact on CNT/metal interface and mechanical properties Computational studies that have not been sufficiently covered although they are essential to research and development The critical issue of CNT dispersion in the metal matrix, as well as a unique way to quantify CNT distribution and subsequently improve control of the processing parameters for obtaining improved properties Carbon Nanotubes: Reinforced Metal Matrix Composites paints a vivid picture of scientific and application achievements in this field. Exploring the mechanisms through which CNTs are enhancing the properties of different metal-based composites, the authors provide a roadmap to help researchers develop MM-CNT composites and choose potential materials for use in emerging areas of technology.
Author: Sie Chin Tjong
Publisher: John Wiley & Sons
ISBN: 3527627006
Category : Technology & Engineering
Languages : en
Pages : 242
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Book Description
Providing a broad insight into the potential applications of carbon nanotubes with metals and ceramic materials as a matrix, this book focuses on the preparation and the microstructural, physical, and mechanical characterizations of such novel nanocomposites. It features information on current synthesis and structure-property-relationships of metals and ceramics reinforced with CNT, organizing the vast array of surveys scattered throughout the literature in a single monograph. With its laboratory protocols and data tables this is invaluable reading for research workers and academics, as well as for applied scientists and industry personnel.
Author: Dale Leigh Lidston
Publisher:
ISBN:
Category :
Languages : en
Pages : 215
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Book Description
In an effort to fully understand the contribution of carbon nanotubes (CNTs) to strength and toughness enhancement in hierarchical nanoengineered composites, particularly steady state Mode I fracture toughness, RTM6 and EPON 862/W epoxy based vertically-aligned carbon nanotube (A-CNT) polymer nanocomposites (A-PNCs) are manufactured. These A-PNCs can be tested to isolate structure-property relationships between the polymer matrix and the A-CNTs without the presence of the micro-scale fibers. Additionally, A-CNT volume fraction can be varied via a densification process to realize 1-30% volume fraction (vf.%) A-PNCs. An investigation of the Mode I initiation fracture toughness via single edge notch beam (SENB) testing of A-PNCs with 1-5 vf.% uniaxially densified A-CNT forests finds that RTM6 baseline and A-PNC samples have a KIc,i of ~ 1 MPa-m1/2, with the exception of 1 vf.% having 1.33 ± 0.09 MPa-m1/2, which needs to be further explored due to process-structure questions of specimen quality. No statistically significant change is observed in EPON 862/W A-PNCs at 1-5 vf.% over baseline specimens having a KIc,i of 1.49 ± 0.06 MPa-m1/2 , indicating that A-CNTs do not offer any toughening at initiation in this system. Scanning electron microscopy of the fracture surface for both A-PNC systems reveals that
Author: Mohamed Berber
Publisher: BoD – Books on Demand
ISBN: 9535124692
Category : Science
Languages : en
Pages : 508
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Book Description
This book shows the recent advances of the applications of carbon nanotubes (CNTs), in particular, the polymer functionalized carbon nanotubes. It also includes a comprehensive description of carbon nanotubes' preparation, properties, and characterization. Therefore, we have attempted to provide detailed information about the polymer-carbon nanotube composites. With regard to the unique structure and properties of carbon nanotubes, a series of important findings have been reported. The unique properties of carbon nanotubes, including thermal, mechanical, and electrical properties, after polymer functionalization have been documented in detail. This book comprises 18 chapters. The chapters include different applications of polymer functionalization CNTs, e.g. photovoltaic, biomedical, drug delivery, gene delivery, stem cell therapy, thermal therapy, biological detection and imaging, electroanalytical, energy, supercapacitor, and gas sensor applications.
Author: Parveen Saini
Publisher: John Wiley & Sons
ISBN: 1119137101
Category : Technology & Engineering
Languages : en
Pages : 684
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Book Description
Since their discovery in 1977, the evolution of conducting polymers has revolutionized modern science and technology. These polymers enjoy a special status in the area of materials science yet they are not as popular among young readers or common people when compared to other materials like metals, paper, plastics, rubber, textiles, ceramics and composites like concrete. Most importantly, much of the available literature in the form of papers, specific review articles and books is targeted either at advanced readers (scientists / technologists / engineers / senior academicians) or for those who are already familiar with the topic (doctoral / postdoctoral scholars). For a beginner or even school / college students, such compilations are bit difficult to access / digest. In fact, they need proper introduction to the topic of conducting polymers including their discovery, preparation, properties, applications and societal impact, using suitable examples and already known principles/knowledge/phenomenon. Further, active participation of readers in terms of "question & answers", "fill-in-the-blanks", "numerical" along with suitable answer key is necessary to maintain the interest and to initiate the "thought process". The readers also need to know about the drawbacks and any hazards of such materials. Therefore, I believe that a comprehensive source on the science / technology of conducting polymers which maintains a link between grass root fundamentals and state-of-the-art R&D is still missing from the open literature.
Author: Siva Yellampalli
Publisher: BoD – Books on Demand
ISBN: 9533074973
Category : Science
Languages : en
Pages : 532
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Book Description
Carbon nanotubes are one of the most intriguing new materials with extraordinary properties being discovered in the last decade. The unique structure of carbon nanotubes provides nanotubes with extraordinary mechanical and electrical properties. The outstanding properties that these materials possess have opened new interesting researches areas in nanoscience and nanotechnology. Although nanotubes are very promising in a wide variety of fields, application of individual nanotubes for large scale production has been limited. The main roadblocks, which hinder its use, are limited understanding of its synthesis and electrical properties which lead to difficulty in structure control, existence of impurities, and poor processability. This book makes an attempt to provide indepth study and analysis of various synthesis methods, processing techniques and characterization of carbon nanotubes that will lead to the increased applications of carbon nanotubes.
