Synthesis and Characterization of Cobalt Carbide Based Nanomaterials

Synthesis and Characterization of Cobalt Carbide Based Nanomaterials
Author: Zachary John Huba
Publisher:
Total Pages: 156
Release: 2014
Genre: Chemistry, Inorganic
ISBN:

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Permanent magnets are used heavily for multiple applications in industry and current electronic technologies. However, the current permanent landscape is muddled by high cost of materials and insufficient magnetic or thermal properties. The primary focus of this dissertation work is the synthesis and optimization of a new permanent magnetic material, in the form of cobalt carbide nanomaterials. The optimization revolved around controlling the crystal phase and particle shape of synthesized cobalt carbide particles; these parameters have significant impact on the observed magnetic properties of magnetic nanoparticles. Co3C was identified to be the preferred crystal phase, leading to better magnetic properties. Cobalt Fumarate was found to be the ideal precursor to synthesize anisotropic Co3C particles and enhance magnetic properties of the synthesized cobalt carbide particles. Lastly, an ethanol based reduction system was employed to develop the greener synthesis of Co and Ni magnetic particles.

Optimizing Cobalt Carbide Based Nanomaterials by Using Nucleating Agents and Statistical Routes

Optimizing Cobalt Carbide Based Nanomaterials by Using Nucleating Agents and Statistical Routes
Author: Turki I. Almugaiteeb
Publisher:
Total Pages:
Release: 2016
Genre: Carbides
ISBN:

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The continuous high demand on permanent magnets in industries opened new research plateau to develop alternative magnetic material. The current used permanent magnet materials in the market still suffer from high cost and insufficient magnetic or thermal properties. The central focus of this dissertation work is the optimization of cobalt carbide based nanomaterial by means of modifying polyol synthesis assisted by nucleation agent and systematic statistics using JMP software tool. In most existing literatures, producing cobalt carbide (Co2C or Co3C) lack reproducibility and consistency resulting in nonsolid magnetic properties results. The practical requirements for cobalt carbide to be used as permanent magnet are high coercivity (Hc), high magnetization (Ms), resulting in a high-energy product (HcxMs). Previous literatures have shown coercivities of 1.5 to 2.5 kOe for cobalt carbides under aggressive temperatures conditions (300oC) or after aligning the particles under magnetic field. A statistical guided method performed a sequence of experiments toward producing high coercivities using surface response design. Primarily, the statistical study to optimize cobalt carbide was made by analyzing experimental condition to fulfill high magnetic properties with tuned conditions as much as possible. Therefore, having the advantage for superior control on process variable when shifting cobalt carbide for scale up production in flow chemistry set up using microreaction system (MMRS). The optimization is based upon selecting the most important conditions in polyol reaction to produce cobalt carbide (Co2C or Co3C) and feed JMP software model e.g. reaction temperature, reaction time, and or precursor concentration ... etc. These factors called (effects) used to design experiments and generate tables to run minimum experiments. Points of each effect (levels) are selected based on previous knowledge and experience with the synthesis. The output called (response) can be any of the magnetic properties of our interest e.g. magnetization (Ms), coercivity (Hc), or energy magnetic product (HcxMs). In the first model fit of cobalt carbide magnetic was studied in a polyol reaction to increase its magnetic energy product and optimize the experimental conditions. The results disclosed increase in magnetic energy product (6.2 MGOe) when validating the prediction model conditions suggested by JMP: shorter reaction time, and lower precursor concentration conditions at maximum reaction temperature. Finally, to my knowledge studying the effect of the nucleating agent to alter cobalt carbide growth have not been studied so far. Therefore, statistical study design using central composite design (CCD) to investigate the nucleating agent effect of silver nitrite on cobalt carbide coercivity was made. The importance of nucleating agent on coercivity is vigorous to attain and control the growth direction of cobalt carbide nanoparticles. This is due to the shape anisotropy contribution to enhance coercivity unlike weak shape anisotropy attributed to agglomeration of nanoparticles demonstrated in previous studies. Enhancement of coercivity reached 3 kOe with aspect ratio control as a function of silver nitrite concentration under lower reaction temperature.

Cobalt

Cobalt
Author: Khan Maaz
Publisher: BoD – Books on Demand
Total Pages: 168
Release: 2017-12-06
Genre: Science
ISBN: 9535136674

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Cobalt is a brittle, hard, silver-grey transition metal with high melting point, hard-wearing at elevated temperatures, good corrosion resistance and improved chemical, magnetic and mechanical properties. This book aims to provide in-depth study and analyses of various synthesis and processing techniques and characterization of cobalt that can lead to its increased applications in recent technology. This book presents deep understanding of the new techniques from basic to the advance level for scientists and engineers. The chapters cover all major aspects about cobalt and its application in material characterization with special emphasis on both theoretical and experimental aspects. This book addresses engineering professionals, students and materials scientists.

Cobalt Compounds and Applications

Cobalt Compounds and Applications
Author: Yasemin Yıldız
Publisher: BoD – Books on Demand
Total Pages: 122
Release: 2019-12-18
Genre: Science
ISBN: 1789845580

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In addition to theoretical information, this book provides information on cobalt compounds and nanoparticles made at selected universities and research centers around the world.This book includes information on new cobalt approaches, nanostructured cobalt, and new catalysts in some reactions and biological systems and technologies.I deeply appreciate the authors? great contributions to this work.We hope that the book will shed light on new horizons for scientists, engineers, and students.

Cobalt-based Magnetic Nanoparticles

Cobalt-based Magnetic Nanoparticles
Author: Mehdi Zamanpour
Publisher:
Total Pages: 134
Release: 2014
Genre: Energy storage
ISBN:

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The ever-increasing desire for more energy attainable from a smaller volume of matter has driven researchers to explore advanced materials at the molecular size. Magnetic materials at the nanometer size scale have been the subject of enormous research effort worldwide for more than half a century. Different magnetic nanoparticles have shown different behavior in the absence and presence of an external magnetic field, which has led them to be categorized as soft or hard magnets. Applications range from medical and biomedical devices to magnetic recording media and magnetic sensing have emphasized the importance of this class of materials. Soft magnetic phases have found application in power generation and magnetic targeted drug delivery, while hard magnets have been subject of extensive research for application as energy storage media. Discovery of the exchange-coupling phenomenon between two adjacent hard and soft magnetic phases has attracted scientists to develop advanced materials for energy storage with no usage of fossil fuels: clean energy. In this Dissertation, synthesis of pure phase, soft FeCo nanoparticles with high magnetic moment and hard phase CoxC nanoparticles possessing high coercivity is reported. The polyol method (chemical co-precipitating at polyhydric alcohol as reducing agent) is used to make FeCo and CoxC nanoparticles and the effects of important reaction kinetics parameters on the structure and magnetic properties of the products are studied. Careful analysis of correlations between these parameters and the properties of the magnetic particles has made synthesis of FeCo and CoxC nanoparticles with desired properties possible. Fabrication of MnAlC-FeCo heterostructures as a rare earth-free alternative for high-performance permanent magnet is also reported. To synthesize MnAlC-FeCo, mechanical alloying and dry mixing of MnAlC and FeCo nanoparticles are accomplished followed by annealing in a furnace. Overall, the achieved results in this work enable synthesis of high moment FeCo and high coercivity CoxC with desired structure and magnetic properties obtained through polyol method. In particular, this Dissertation provides the technique to fabricate cobalt carbide nanoparticles without using rare earth elements as a catalyst or as heterogeneous seed nuclei at any stage of the processing.

Synthesis and Characterization of Cobalt Nanoparticles for Biomedical Applications

Synthesis and Characterization of Cobalt Nanoparticles for Biomedical Applications
Author: Hari Lal Bhatta
Publisher:
Total Pages: 102
Release: 2011
Genre: Cobalt
ISBN:

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Nanomaterial research has attracted a great deal of enthusiasm from the public because of the applications of nanomaterials in various areas of science such as physics, chemistry, medicine, and materials science. Biocompatible and nontoxic cobalt nanoparticles have biomedical applications including drug delivery, cell and deoxyribonucleic acid (DNA) separation, gene cloning, and magnetic resonance imaging. The main aim of this research project is to produce contamination-free cobalt nanoparticles for biomedical applications. Pulsed Laser Deposition (PLD) technique was used to fabricate contamination-free cobalt nanoparticles directly from cobalt foil. A KrF laser having laser pulses of wavelength 248 nm, pulse duration of 20 ns, and repetition rate of 10 Hz was employed in pulsed laser deposition technique. The synthesized cobalt nanoparticles were characterized using UV-Vis absorption spectroscopy and dynamic laser light scattering (DLLS). The synthesized cobalt nanoparticles were stabilized in glucose solutions of various concentrations. The UV-Vis absorption peak around 268 nm confirms the presence of cobalt nanoparticles in aqueous media. The DLLS size distribution of cobalt nanoparticles has been found in the range between 355 nm to 465 nm with variation of growth parameters such as laser energy, number of shot, and glucose concentration. Glucose stabilized cobalt nanoparticles have been successfully functionalized with DNA and laser modified DNA. The binding of cobalt nanoparticles with DNA plays an important role in the future for gene delivery.