Direct Magnetoelectric Effect in Bilayered Ceramic Composites Based on Mn0.4Zn0.6Fe2O4 Ferrimagnet and PbZr0.53Ti0.47O3 Ferroelectric

2021 ◽  
Author(s):  
A. V. Kalgin
Keyword(s):  
Magnetoelectric Effect ◽  
Ceramic Composites

The Direct and the Converse Magnetoelectric Effect in Multiferroic Cobalt Ferrite-Barium Titanate Ceramic Composites

2016 ◽  
Vol 99 (11) ◽  
pp. 3623-3631 ◽  
Author(s):  
Morad Etier ◽  
Vladimir V. Shvartsman ◽  
Soma Salamon ◽  
Yanling Gao ◽  
Heiko Wende ◽  
...  
Keyword(s):  
Barium Titanate ◽  
Cobalt Ferrite ◽  
Magnetoelectric Effect ◽  
Ceramic Composites ◽  
Barium Titanate Ceramic ◽  
Titanate Ceramic

Magnetoelectric properties in bulk and layered composites

2015 ◽  
Vol 32 (3) ◽  
pp. 110-114 ◽  
Author(s):  
Piotr Guzdek ◽  
Marek Wzorek
Keyword(s):  
Polyvinylidene Fluoride ◽  
Magnetoelectric Effect ◽  
Materials Science ◽  
Functional Materials ◽  
Solid State Reaction Method ◽  
Ceramic Composites ◽  
Sem Analysis ◽  
Content Type ◽  
Magnetoelectric Composites ◽  
Magnetoelectric Properties

Purpose – The purpose of the paper was to present a comparative study on the microstructure and magnetoelectric effect of new magnetoelectric composites based on TbFe2 compound and Ni0.3Zn0.62Cu0.08Fe2O4, CoFe2O4 ferrites as a magnetostrictive phase, Pb(Fe1/2Ta1/2)O3 (PFT), Pb(Fe1/2Nb1/2)O3 relaxors as a ferroelectric phase and polyvinylidene fluoride (PVDF) as piezoelectric phase. Design/methodology/approach – The ceramic components of composites were prepared by the standard solid-state reaction method. The intermetallic compound TbFe2 was prepared with an arc melting system with a contact-less ignition in a high purity argon atmosphere. The metal – ceramic – polymer composites were prepared in a container in which powder of PVDF were dissolved in N,N-dimethylformamide with continuous mixing and at the controlled temperature. Ceramic composites were prepared as bulk samples and multilayer tape cast and co-sintered laminates. The microstructure of the composites was investigated using scanning electron microscopy (SEM). The magnetoelectric effect of the composites was evaluated at room temperature by means of the dynamic lock-in method. Findings – SEM analysis revealed a dense, fine-grained microstructure and uniform distribution of the metallic, ferrite and relaxor grains in the bulk composites. The SEM image for multilayer composite illustrates the lack of cracks or delaminations at the phase boundaries between the well-sintered ferrite and relaxor layers. For all studied composites, the magnetoelectric coefficients at a lower magnetic field increase, reaches a maximum and then decreases. Originality/value – The progress in electronic technology is directly linked to advances made in materials science. Exploring and characterizing new materials with interesting magnetoelectric properties, in the rapidly growing field of functional materials, is an important task. The paper reports on processing, microstructure and magnetoelectric properties of novel magnetoelectric composites.

Magnetoelectric Effect of the Ba0.80Sr0.2TiO3-CoFe2O4 Ceramic Composites by Molten-Salt Synthesis Method

2012 ◽  
Vol 268-270 ◽  
pp. 63-66
Author(s):  
Wei Rao ◽  
Ding Guo Li ◽  
Hong Chun Yan
Keyword(s):  
Magnetic Field ◽  
Particle Size ◽  
Molten Salt ◽  
Coupling Coefficient ◽  
Magnetoelectric Effect ◽  
Synthesis Method ◽  
Ceramic Composites ◽  
Molten Salt Synthesis ◽  
Interfacial Coupling ◽  
Bias Magnetic Field

This paper presents the structural, ferroelectric, ferromagnetic, resonance and magnetoelectric (ME) properties of multilayered ME composites fabricated using molten-salt synthesis method. The compositions corresponding to CoFe2O4 (CFO) with particle size of ~ 150 nm and Ba0.8Sr0.2TiO3 (BST) with particle size of ~ 100 nm were chosen as ferromagnetic and ferroelectric phases. The largest direct magnetoelectric (DME) and converse magnetoelectric (CME) coefficients of the multilayered ME composite were, respectively, 36 μV/cm•Oe at a bias magnetic field of 2800 Oe and 1.16×10-3G/V at a frequency of 30 kHz. In addition, the corresponding interfacial coupling coefficient was calculated to be 3.2×10-5. For the multilayered ME composite, the resonance frequency of 4.97 MHz and bandwidth of 30 kHz were obtained using capacitance-frequency spectrum method.

Microstructural Evaluation of Silicon Carbide Whisker Reinforced Alumina Fabricated with Carbon-Coated Whiskers

1991 ◽  
Vol 49 ◽  
pp. 920-921
Author(s):  
K. B. Alexander ◽  
P. F. Becher
Keyword(s):  
Silicon Carbide ◽  
High Resolution Electron Microscopy ◽  
Ceramic Composites ◽  
Interface Debonding ◽  
Resolution Electron ◽  
Microstructural Evaluation ◽  
Carbon Coated ◽  
Electron Energy Loss ◽  
Interfacial Films ◽  
Debonding Process

The presence of interfacial films at the whisker-matrix interface can significantly influence the fracture toughness of ceramic composites. The film may alter the interface debonding process though changes in either the interfacial fracture energy or the residual stress at the interface. In addition, the films may affect the whisker pullout process through the frictional sliding coefficients or the extent of mechanical interlocking of the interface due to the whisker surface topography.Composites containing ACMC silicon carbide whiskers (SiCw) which had been coated with 5-10 nm of carbon and Tokai whiskers coated with 2 nm of carbon have been examined. High resolution electron microscopy (HREM) images of the interface were obtained with a JEOL 4000EX electron microscope. The whisker geometry used for HREM imaging is described in Reference 2. High spatial resolution (< 2-nm-diameter probe) parallel-collection electron energy loss spectroscopy (PEELS) measurements were obtained with a Philips EM400T/FEG microscope equipped with a Gatan Model 666 spectrometer.

HREM interface studies in SiC-whisker-reinforced Al2O3 and Si3N4 ceramics

1988 ◽  
Vol 46 ◽  
pp. 734-735
Author(s):  
W. Braue ◽  
R.W. Carpenter ◽  
D.J. Smith
Keyword(s):  
Analytical Data ◽  
Base Material ◽  
High Strength ◽  
Ceramic Composites ◽  
Good Thermal Stability ◽  
All Ceramic ◽  
Sic Whiskers ◽  
Base Composite ◽  
C 30 ◽  
Si3n4 Ceramics

Whisker and fiber reinforcement has been established as an effective toughening concept for monolithic structural ceramics to overcome limited fracture toughness and brittleness. SiC whiskers in particular combine both high strength and elastic moduli with good thermal stability and are compatible with most oxide and nonoxide matrices. As the major toughening mechanisms - crack branching, deflection and bridging - in SiC whiskenreinforced Al2O3 and Si3N41 are critically dependent on interface properties, a detailed TEM investigation was conducted on whisker/matrix interfaces in these all-ceramic- composites.In this study we present HREM images obtained at 400 kV from β-SiC/α-Al2O3 and β-SiC/β-Si3N4 interfaces, as well as preliminary analytical data. The Al2O3- base composite was hotpressed at 1830 °C/60 MPa in vacuum and the Si3N4-base material at 1725 °C/30 MPa in argon atmosphere, respectively, adding a total of 6 vt.% (Y2O3 + Al2O3) to the latter to promote densification.

Biomimetic materials: An introduction

1992 ◽  
Vol 50 (2) ◽  
pp. 1020-1021 ◽  
Author(s):  
M. Sarikaya ◽  
J. T. Staley ◽  
I. A. Aksay
Keyword(s):  
Self Assembly ◽  
Structural Control ◽  
Hierarchical Structures ◽  
Ceramic Composites ◽  
Advanced Materials ◽  
Length Scale ◽  
Spider Webs ◽  
Biomimetic Materials ◽  
Synthetic Materials ◽  
All Ceramic

Biomimetics is an area of research in which the analysis of structures and functions of natural materials provide a source of inspiration for design and processing concepts for novel synthetic materials. Through biomimetics, it may be possible to establish structural control on a continuous length scale, resulting in superior structures able to withstand the requirements placed upon advanced materials. It is well recognized that biological systems efficiently produce complex and hierarchical structures on the molecular, micrometer, and macro scales with unique properties, and with greater structural control than is possible with synthetic materials. The dynamism of these systems allows the collection and transport of constituents; the nucleation, configuration, and growth of new structures by self-assembly; and the repair and replacement of old and damaged components. These materials include all-organic components such as spider webs and insect cuticles (Fig. 1); inorganic-organic composites, such as seashells (Fig. 2) and bones; all-ceramic composites, such as sea urchin teeth, spines, and other skeletal units (Fig. 3); and inorganic ultrafine magnetic and semiconducting particles produced by bacteria and algae, respectively (Fig. 4).

Observation of solid-state reaction between a thin yttria film and a (0001) α-alumina substrate

1994 ◽  
Vol 52 ◽  
pp. 644-645
Author(s):  
J. R. Heffelfinger ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Solid State Reaction ◽  
Yttrium Aluminum Garnet ◽  
Secondary Phase ◽  
Ceramic Composites ◽  
Alumina Substrate ◽  
Transmission Electron ◽  
Alumina Fibers ◽  
Optical Applications

Transmission-electron microscopy (TEM), scanning-electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDS) were used to investigate the solid-state reaction between a thin yttria film and a (0001) α-alumina substrate. Systems containing Y2O3 (yttria) and Al2O3 (alumina) are seen in many technologically relevant applications. For example, yttria is being explored as a coating material for alumina fibers for metal-ceramic composites. The coating serves as a diffusion barrier and protects the alumina fiber from reacting with the metal matrix. With sufficient time and temperature, yttria in contact with alumina will react to form one or a combination of phases shown by the phase diagram in Figure l. Of the reaction phases, yttrium aluminum garnet (YAG) is used as a material for lasers and other optical applications. In a different application, YAG is formed as a secondary phase in the sintering of AIN. Yttria is added to AIN as a sintering aid and acts as an oxygen getter by reacting with the alumina in AIN to form YAG.

Characterization of microwave-sintered ceramic composites

1993 ◽  
Vol 51 ◽  
pp. 1136-1137
Author(s):  
X. Zhang ◽  
Y. Pan ◽  
T.T. Meek
Keyword(s):  
Matrix Material ◽  
Maximum Output Power ◽  
Ceramic Matrix Composite ◽  
Ceramic Composites ◽  
Processing Technique ◽  
Structure Characterization ◽  
Alumina Powder ◽  
Maximum Output ◽  
Sintered Ceramic

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

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