High aspect ratio nanoparticles include nanotubes and nanowires, with various shapes, such as helices, zigzags, belts, or perhaps nanowires with diameter that varies with length.
Small-aspect ratio morphologies include spherical, oval, cubic, prism, helical, or pillar. Collections of many particles exist as powders, suspension, or colloids [44]. For example, magnetic nanoparticles tend to cluster, forming an agglomerate state, unless their surfaces are coated with a non-magnetic material. In an agglomerate state, nanoparticles may behave as larger particles, depending on the size of the agglomerate.
Hence, it is evident that nanoparticle agglomeration, size and surface reactivity, along with shape and size, must be taken into account when deciding considering health and environmental regulation of new materials [44]. As a widely studied nanomaterial, Al2O3 nanoparticles have been applied in catalysis, nanocomposites, polymer modification, functionalization of, heat transfer fluids and waste water treatment. Structure of Al2O3 is shown in Figure In addition, Al2O3 nanoparticles have featured in biological applications, such as biosensors, biofiltration and drug delivery, antigen delivery for immunization purposes and bactericides [49].
Silicon Carbide SiC Silicon carbide is an important non-oxide ceramic which has diverse industrial applications. In fact, it has exclusive properties such as high hardness and strength, chemical and thermal stability, high melting point, oxidation resistance, high erosion resistance.
Silicon carbide SiC is a unique material that maintains high corrosion resistance at temperatures well beyond the typical high temperature limits for superalloys [50]. Silicon carbide SiC is well known to be a wide band gap semiconducting material consisting of different polytypes [51].
The crystal structures of zirconia are monoclinic, tetragonal, and cubic [53]. This polymorphic transformation caused modifications in the density and physical properties of zirconia. Zirconia with tetragonal and cubic structures has higher density which is around 6. Table : Chemical composition of carbon steel. Some properties of used alumina are: purity Nano alumina was obtained from Guangzhou Jiechuang Trading Co.
Nano zirconia was obtained from Guangzhou Jiechuang Trading Co. Square specimens were obtained as a final specimen shape. Grinding and Polishing The specimens were ground with SiC papers in sequence of , , , , and grit to get flat and scratch-free surface by Grinder and Polisher MoPao E shown in Fig. The polished specimens were dried and immersed in ethanol liquid and then used for electrochemical investigation.
All powders were weighted by a sensitive balance shown in Fig. Homogenize solutions were obtained, as shown in Fig. Nitrogen gas purity Atomizer which contains container for suspension solution and nozzle for spraying which is directed onto the specimen surface about 5 cm above specimens Fig. After spraying, the coated specimen was heated to improve the adhesion between the coating layer and the metal. The spraying of suspension achieved by airbrush is shown in Fig.
These attractive forces mainly arise from Van derWaals interactions between the tip and the surface [55]. The electron beam can be focused by a magnetic field from micro to nanometer level, thus enabling the measurement of surface topography. Reference and counter electrodes were Pt and saturated calomel electrode SCE , respectively. The corrosion cell is shown in Fig. Corrosion current density i corr and corrosion potential values Ecorr were determined from the polarization curve by Tafel extrapolation method.
Cyclic polarization carried out to estimate initiation and propagation of pits by forward and reveres scan of polarization up to mV. The corrosion test is shown in Fig.
Cyclic polarization will be interoperated to know the probability to pitting corrosion. The two and three dimensional AFM morphologies of cross sectional profile for polished carbon steel surface reference specimen , coated carbon steel by nanoparticles Al2O3, SiC, ZrO2 as a single, binary and ternary coatings are shown in Figs. Cross-sectional images for roughness are shown in Appendix A. It can be seen only some scratches due to grinding and polishing process. This figure also displays that the average size of the particle is Figures to show the AFM images for coated surfaces.
Figures to show the SEM which give additionally more clear shape of the clustering and particles on metal surface. Figure indicate the steel surface without deposition of any nano particles, while other images show the distribution of deposited particles on steel surface. These images show the uniform distribution of nano particles which applied by cold spraying method. With the same number of spraying at the same time and distance, we get different thickness of coatings depending on particle sizes of coat components.
The presence of alumina in coating constitutes gave the high thickness compared with other coatings due to agglomeration of alumina as illustrated in SEM images.
The corrosion potential of uncoated specimen is From this figure, it can be seen that the curves of coated surfaces with alumina and zirconia shifted toward lower current densities and more positive values of potential. The curve of coated carbon steel with nanoparticles SiC gave lower effect than other coatings, but one can be observed the protection and breakdown on cathodic and anodic sites.
The measured corrosion parameters from these curves are listed in Table , these data indicate that the corrosion potentials became more positive values, and the corrosion current densities were decreased. This phenomenon leads to accumulation of oxygen molecules at cathode and then concentration polarization will occur.
Table : Measured corrosion data of uncoated and coated specimens with single coatings in seawater. The data of corrosion rate indicate that the nanoparticle coatings led to decreasing in corrosion rate of carbon steel as shown in Table Furthermore, surface porosity fraction was estimated by both potentiodynamic polarization and nano-indentation measurements.
The later result is in good agreement with the result of polarization resistance. Table : Calculated corrosion parameters for uncoated and coated carbon steel with single coatings. Table : Measured corrosion data of uncoated and coated specimens with binary coatings in seawater. Furthermore, the protection efficiency for binary coating Alumina-silicon carbide has a large value, this gives the best protection for carbon steel surface than silicon carbide-Zirconium and the last is best than Alumina-Zirconium.
Table : Calculated corrosion parameters for uncoated and coated carbon steel with binary coatings. This figure indicates that the curve of coated specimen shifted toward more positive potentials and has significant effect on cathodic region.
Corrosion parameters of uncoated and coated specimens are listed in Table These data indicates that the coated specimen has corrosion potential Both cathodic and anodic Tafel slopes were decreased. Other parameters for coated surface were calculated to enhance the role of coating, such as polarization resistance, corrosion rate, protection efficiency and porosity percentage as listed in Table The polarization resistance was decreased because it is depended on Tafel slope values that decreased due to different reactions which can takes place at cathodic and anodic sites as illustrated in Fig.
While the corrosion rate was decreased and get protection efficiency equal to For measuring the pits forming possibilities, a cyclic polarization procedure was obeyed as shown in Figure ; where EP is a pitting potential and ER is a repassivation potential. The schematic polarization curve in Figure shows the case of a spontaneously passive material, meaning that a protective passive film is present on the metal surface at the open circuit or corrosion potential Ecorr.
During upward scanning, breakdown occurs, and a stable pit starts growing at the pitting potential EP, where the current increases sharply from the passive current level and, on reversal of the scan direction, repassivates at ER where the current drops back to low values representative of passive dissolution. Figure shows the cyclic polarization of uncoated carbon steel. From this figure, can be seen that the reverse scan appears to the right of forward scan and the potential of reverse scan mV was more negative than potential of forward scan mV.
The EP and ER are This means that the passive zone finished at The pitting nucleation and a right loop are obtained; also the return potential at mV that is characteristic of pitting propagation and a negative hysteresis due to the reversible damage by pitting are also observed.
If the protection potential is more negative than the pitting potential, pitting could occur. The size of the pitting loop is rough indication of pitting tendency; the larger the loop, the greater the tendency to pit. Figures to show the cyclic polarization of single coatings with alumina, silicon carbide and zirconia respectively. This means that the damage which occurs in passive film could not repairing it. In the case of nano zirconia coated specimen, can be seen that the reverse scan appears at more positive potentials than forward scan with pitting potential - This result shows that a stable oxide film is formed during the forward scan.
Finally, it can be say that the coating with alumina and zirconia better than SiC. The crystalline phase has similar composition and dielectric permittivity as that of the glass phase. It is concluded from impedance results that the glass phase is the major contributor to the composite conductivity. Sol—gel technology is a contemporary advancement in science that requires taking a multidisciplinary approach with regard to its various applications.
This book highlights some applications of the sol—gel technology, including protective coatings, catalysts, piezoelectric devices, wave guides, lenses, high-strength ceramics, superconductors, synthesis of nanoparticles, and insulating materials. In particular, for biotechnological applications, biomolecules or the incorporation of bioactive substances into the sol—gel matrix has been extensively studied and has been a challenge for many researchers.
Some sol—gel materials are widely applied in light-emitting diodes, solar cells, sensing, catalysis, integration in photovoltaic devices, and more recently in biosensing, bioimaging, or medical diagnosis; others can be considered excellent drug delivery systems.
The goal of an ideal drug delivery system is the prompt delivery of a therapeutic amount of the drug to the proper site in the body, where the desired drug concentration can be maintained. The interactions between drugs and the sol—gel system can affect the release rate. In conclusion, the sol—gel synthesis method offers mixing at the molecular level and is able to improve the chemical homogeneity of the resulting composite.
This opens new doors not only regarding compositions of previously unattainable materials, but also to unique structures with different applications.
Sol-gel processing is a low temperature, low cost wet chemistry route to a range of different materials, particularly glassy and ceramic oxides, including nanoparticles and powders, fibers, thin films and membranes, or monoliths and composites. Thin films and coatings represent by far the most important category of sol-gel derived products with optical, electronic and magnetic functionalities, for example photoresist and dielectric spin-on-glass layers, flat screen displays, anti-reflection, conducting and magnetic disk coatings, as well as photochromic, electrochromic and photovoltaic coatings.
Sol-gel derived materials are homogeneous at the molecular level and are a good example of a bottom-up approach to materials synthesis. There is increasing need of new optical and photonic materials with improved performance, where molecular level homogeneity and easy fabrication in film form may be especially convenient, highlighting a decisive advantage of sol-gel over other more established technologies to obtain graded index optical components, solar control coatings, phosphors, glass ceramics or multilayer photonic structures.
There is no book available yet which focuses in particular on optical and photonic sol-gel derived materials. This is what makes this book unique at this point for those especially or exclusively interested in optical and photonic functional materials and applications. This book represents an important tool to update scientists and engineers with recent advances in the rapidly evolving field of optical and photonic materials, components and devices.
Reviews wide range of sol-gel derived coatings including reflective and anti-reflective, self-cleaning, and electrochromic Discusses latest advances in sol-gel derived photonic crystals including one dimensional, two dimensional, and three dimensional structures Addresses key applications in solid state lighting, solar cells, sensors, fiber optics, and magneto-optical devices. The Springer Handbook of Nanomaterials covers the description of materials which have dimension on the "nanoscale".
The description of the nanomaterials in this Handbook follows the thorough but concise explanation of the synergy of structure, properties, processing and applications of the given material. The Handbook mainly describes materials in their solid phase; exceptions might be e. The materials are organized by their dimensionality. Zero dimensional structures collect clusters, nanoparticles and quantum dots, one dimensional are nanowires and nanotubes, while two dimensional are represented by thin films and surfaces.
The chapters in these larger topics are written on a specific materials and dimensionality combination, e. Chapters are authored by well-established and well-known scientists of the particular field. They have measurable part of publications and an important role in establishing new knowledge of the particular field.
Ceramic nanocomposites have been found to have improved hardness, strength, toughness and creep resistance compared to conventional ceramic matrix composites.
Ceramic nanocomposites reviews the structure and properties of these nanocomposites as well as manufacturing and applications. Part one looks at the properties of different ceramic nanocomposites, including thermal shock resistance, flame retardancy, magnetic and optical properties as well as failure mechanisms.
Part two deals with the different types of ceramic nanocomposites, including the use of ceramic particles in metal matrix composites, carbon nanotube-reinforced glass-ceramic matrix composites, high temperature superconducting ceramic nanocomposites and ceramic particle nanofluids. Part three details the processing of nanocomposites, including the mechanochemical synthesis of metallic—ceramic composite powders, sintering of ultrafine and nanosized ceramic and metallic particles and the surface treatment of carbon nanotubes using plasma technology.
Part four explores the applications of ceramic nanocomposites in such areas as energy production and the biomedical field. With its distinguished editors and international team of expert contributors, Ceramic nanocomposites is a technical guide for professionals requiring knowledge of ceramic nanocomposites, and will also offer a deeper understanding of the subject for researchers and engineers within any field dealing with these materials.
Reviews the structure and properties of ceramic nanocomposites as well as their manufacturing and applications Examines properties of different ceramic nanocomposites, as well as failure mechanisms Details the processing of nanocomposites and explores the applications of ceramic nanocomposites in areas such as energy production and the biomedical field. Fundamental Biomaterials: Ceramics provides current information on ceramics and their conversion from base materials to medical devices.
Initial chapters review biomedical applications and types of ceramics, with subsequent sections focusing on the properties of ceramics, and on corrosion, degradation and wear of ceramic biomaterials. The book is ideal for researchers and professionals in the development stages of design, but is also helpful to medical researchers who need to understand and communicate the requirements of a biomaterial for a specific application.
This title is the second in a three volume set, with each reviewing the most important and commonly used classes of biomaterials and providing comprehensive information on material properties, behavior, biocompatibility and applications.
In addition, with the recent introduction of a number of interdisciplinary bio-related undergraduate and graduate programs, this book will be an appropriate reference volume for large number of students at undergraduate and post graduate levels Provides current information on findings and developments of ceramics and their conversion from base materials to medical devices Includes analyses of the types of ceramics and a discussion of a range of biomedical applications and essential properties, including information on corrosion, degradation and wear, and lifetime prediction of ceramic biomaterials Explores both theoretical and practical aspects of ceramics in biomaterials.
Skip to content. The rare-earth dopant nucleates the growth of the nano-crystalline phase con- glassy hosts. The size and shape of the nano-crystals have been evaluated by means of the transmission electron microscopy TEM , X-ray diffraction XRD and Raman scattering techniques, e.
Driesen chem. Tikhomirov et al. The typical size of the e. The optical set-ups have been described elsewhere reasons discussed further. The high symmetry of the dopant site allows a contribution of vibronic The data presented in Fig.
The side components that almost either completely or substantially quenched in other materials. The the multiple infrared wavelengths.
It is seen from Eq. On the other hand, Wnrn T can also be expressed by Eq. A structured deep between 1. References [1] V. Tikhomirov, D. Furniss, I. Reaney, M. Beggiora, M. Ferrari, M.
Montagna, R. Rolli, Appl. Tikhomirov, K. Driesen, C. Status Sol. Driesen, V. Tikhomirov, J. Koch, D. Wand, B. Chichkov, Phys. The maximal phonon energy of the GC host equals to cm.
Mattarelli, V. Tikhomirov, M. Montagna, E.
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