China
Africa
Explore chapters and articles related to this topic
Magnetics and Piezoelectrics
Published in Debasish Sarkar, Nanostructured Ceramics, 2018
In principle, the magnetization is a nanoscale phenomenon, and thus nanocrystalline material carries technological significance in enhancing the performance of existing bulk materials. Around the globe, researchers are exploring size minimization toward nanoscale which consists of different geometries and crystallinity for high performance devices. Magnetism of ferro and ferrimagnetic material depends on the volume of the particles, and thus the bulk magnet always experiences multiple magnetic domain structures. However, below a certain critical radius, nanocrystal behaves as a single-domain state and hence the domain wall resistance can avoid and effectively work at high frequency. A brief illustration on the transition of multidomain to single-domain (SD) with respect to the relation between coercivity and particle size is represented in Figure 5.3. Above Curie temperature, (Tc), the magnetic spins are randomly distributed that lead to zero magnetization, where same magnetic material develops domain walls below Tc.
Recent Development in Industrial Scale Fabrication of Nanoparticles and Their Applications
Published in Uma Shanker, Manviri Rani, Liquid and Crystal Nanomaterials for Water Pollutants Remediation, 2022
Sandeep Kumar, Bandna Bharti, Xiaoxiong Zha, Feng Ouyang, Peng Ren
Based on the properties and structures, nanoparticles have been classified in different phrases, which are based on dimensionality (0, 1, 2 and 3D), and on the basis of origin (natural and artificial) (Kufer and Konstantatos 2016, Shao et al. 2020). Furthermore, natural nanoparticles have been divided into two parts which are organic and inorganic nanoparticles, while artificial nanoparticles may divide into four parts, such as metal, carbon-based, composites and dendrimers (Zhang et al. 2020). Classification of the nanomaterials has been shown in Figure 1, which is based on the dimensionality of nanoparticles. Because of dimensionality changes, the surface area, as well as properties of the materials, also changes. Nanomaterial systems in fluid crystals have been attracting growing interest in recent years because of the ability to add functionalities to liquid crystals through the properties of the scattered particles, and also the self-organization of fluid crystals can be used to form ordered nanomaterial structures. A nanocrystalline material has a significant fraction of crystal grains in the nanoscale. The need for high surface area, excellent electrical conductivity, high sensitivity, and catalytic activity was the key behind the extent of its usefulness and numerous applications. They are classified as nanocomposites, nanofoam, nanoporous and nanocrystalline materials on the basis of the phases of matter contained by the nanostructured materials. Nanocomposites are called solid materials as they contain one physically or chemically distinct region with at least one nanoscale-dimensioned region. A liquid or solid matrix is contained in nanofoams that are filled with a gaseous phase, and one of the two phases has nanoscale dimensions. Nanoporous materials, cavities with nanoscale dimensions, are regarded as nanoporous. At the nanoscale, nanocrystalline materials have crystal grains. Despite these obstacles, a controlled assembly of crystals using soft materials, such as proteins, DNA, nanoparticles and other colloids, would make novel nanomaterials extremely useful. Liquid crystal nanomaterials have been used in oils, lubricants, formation grease, etc.
Enhancement of metallurgical and mechanical properties due to grain refinement in the compressive residual stress developed surface after the laser shock peening process: a review
Published in Canadian Metallurgical Quarterly, 2023
In modern industries, there is a high requisite for materials that possess balanced mechanical properties such as residual stress, good ductility, and strength. Researcher Ye C et al. reported that even though the nanocrystalline material possesses a low ductility value, it has demand in the industries owing to its enhanced rate of strength, and can be produced by severe plastic deformation [73]. Material strength can be increased by the creation of dense nanoprecipitates and locking the mobile dislocation in the case of the WLSP method. Whereas the creation of dense deformation twins and pressurisation in defect recovery help to enhance the properties of the material in the case of the CLSP method. Even though an enhanced rate of benefits is imparted in the material by CLSP and WLSP methods, there are very few studies performed in the open literature.
Anisotropic grain growth kinetics in nanocrystalline nickel
Published in Philosophical Magazine Letters, 2018
The instrumental-broadening-corrected XRD peak contains contributions from size (arising from the limited crystallite size) and strain (arising from the presence to defects). To determine the crystallite size (for nanocrystalline material this is equivalent to grain size), it is essential to separate out the contribution of strain broadening [14–18]. There are various approaches available to deconvolute the size and strain contribution. The simplified breadth method is the simplest way to determine the grain size from individual XRD peaks after separating the strain contribution [19]. In this method, XRD peaks are fitted with a pseudo Voigt (pV) function to determine the integral breadths. In a pV function, there are two components: Gaussian (G) and Lorentzian (L). In the single-peak line-profile-analysis method, the crystallite size (D) is determined from the Lorentzian part of the integral breadth (βL) by the relation:where K is a constant = 0.95, λ is the wavelength of the X-ray (0.15417 nm), and θ is the Bragg angle of the XRD peak.