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Article
Publication date: 12 April 2011

Robert Bogue

This paper aims to describe the technology and applications of nanocomposite materials.

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Abstract

Purpose

This paper aims to describe the technology and applications of nanocomposite materials.

Design/methodology/approach

This paper discusses products, applications and technological developments in polymer, ceramic and metal nanocomposites. It concludes with a brief consideration of electronic component applications.

Findings

It is shown that polymer nanocomposites and the materials used in their production are commercially available and finding applications in several industries, including automotive, military, food, electronics and leisure, due to their enhanced mechanical, electrical and thermal properties. Ceramic and metallic nanocomposites are at an earlier stage of development and a critical issue to resolve is optimising the dispersion of nanomaterials in the matrices. Passive electronic components based on nanocomposite materials are under development.

Originality/value

The paper provides a review of the rapidly developing field of nanocomposite technology.

Details

Assembly Automation, vol. 31 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

Article
Publication date: 2 May 2017

Maruti K. Rendale, S.N. Mathad and Vijaya Puri

The present communication aims to investigate the influence of cobalt substitution on the structural, mechanical and elastic properties of nickel–zinc ferrite thick films. The…

Abstract

Purpose

The present communication aims to investigate the influence of cobalt substitution on the structural, mechanical and elastic properties of nickel–zinc ferrite thick films. The changes observed in the crystallite size (D), lattice constant (a), texture coefficient [TC(hkl)] and mechanical and elastic properties of the thick films due to cobalt substitution have been reported systematically.

Design/methodology/approach

Ni–Zn ferrites with the stoichiometric formula Ni0.7−xCoxZn0.3Fe2O4 (where, x = 0, 0.04, 0.08, 0.12, 0.16 and 0.20) were synthesized via solution combustion technique using sucrose as the fuel and poly-vinyl-alcohol as the matrix material. The thick films of the ferrites were fabricated on alumina substrates by the screen printing method. The thickness of the films was 25 μm, as measured by the gravimetric method. The thick films were subjected to X-ray diffraction and Fourier transform infrared spectroscopy.

Findings

The detailed study of variation of lattice parameter (a), sintering density, micro-strain and elastic properties with cobalt (Co+2) substituted was carried out. The remarkable increase in lattice parameter (from 8.369 A° to 8.3825 A°), bulk density and average grain size (69-119 nm) with the cobalt content was due to larger ionic radius of Co2+ compared to Ni2+. Texture analysis [TC(hkl)] reveals all thick films have adequate grain growth in the (311) plane direction. The main absorption bands of spinel ferrite have appeared through infrared absorption spectra recorded in the range of 300-700 cm−1.

Originality/value

The variation in stiffness constants (for isotropic material, C11 = C12), longitudinal elastic wave (Vl), transverse elastic wave (Vt), mean elastic velocity (VMean), rigidity modulus (G), Poisson’s ratio(s) and Young’s modulus (E) with cobalt (Co+2) composition has been interpreted in terms of binding forces found.

Details

Microelectronics International, vol. 34 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 23 January 2009

M.K. Rendale, S.D. Kulkarni and Vijaya Puri

The aim of this paper is to investigate permittivity of nano structured Ni0.7‐xCoxZn0.3Fe2O4 thick films at microwave frequencies.

Abstract

Purpose

The aim of this paper is to investigate permittivity of nano structured Ni0.7‐xCoxZn0.3Fe2O4 thick films at microwave frequencies.

Design/methodology/approach

Nanosized Ni0.7‐xCoxZn0.3Fe2O4 ferrites with x=0, 0.04, 0.08 and 0.12 were prepared by sucrose precursor technique using the constituent metal nitrates. Thick films of the ferrites were fabricated on alumina substrates by screen‐printing technique. Microwave dielectric constant (ε′) and the loss factor (ε″) for the thick films were measured by VSWR slotted section method in the 8‐18 GHz range of frequencies. Microwave attenuation properties were studied using a waveguide reflectometer set up.

Findings

Both the ε′ and ε″ were found to vary with frequency and composition x. It is observed that, value of ε′ increases with increase in x, due to the increase in bulk density and reduction in porosity of the material, that resulted due to the substitution of cobalt in Ni‐Zn ferrite. The microwave transmission loss offered by the thick films was found to increase with the increase in cobalt concentration x. Within the band width of 4 GHz (from 12‐16 GHz), all the films except that with x=0.04 offered the reflection loss of less than 3 dB.

Originality/value

The dielectric constant of Ni0.7‐xCoxZn0.3Fe2O4 thick films have been reported for the first time. These thick films provide scope for cost effective planar ferrite devices.

Details

Microelectronics International, vol. 26 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 5 January 2022

Thejas Ramakrishnaiah, Prasanna Gunderi Dhananjaya, Chaturmukha Vakwadi Sainagesh, Sathish Reddy, Swaroop Kumaraswamy and Naveen Chikkahanumajja Surendranatha

This paper aims to study the various developments taking place in the field of gas sensors made from polyaniline (PANI) nanocomposites, which leads to the development of…

Abstract

Purpose

This paper aims to study the various developments taking place in the field of gas sensors made from polyaniline (PANI) nanocomposites, which leads to the development of high-performance electrical and gas sensing materials operating at room temperature.

Design/methodology/approach

PANI/ferrite nanocomposites exhibit good electrical properties with lower dielectric losses. There are numerous reports on PANI and ferrite nanomaterial-based gas sensors which have good sensing response, feasible to operate at room temperature, requires less power and cost-effective.

Findings

This paper provides an overview of electrical and gas sensing properties of PANI/ferrite nanocomposites having improved selectivity, long-term stability and other sensing performance of sensors at room temperature.

Originality/value

The main purpose of this review paper is to focus on PANI/ferrite nanocomposite-based gas sensors operating at room temperature.

Details

Sensor Review, vol. 42 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 4 May 2012

Mirjana S. Damnjanović, Ljiljana D. Živanov, Snezana M. Djurić, Andrea M. Marić, Aleksandar B. Menićanin, Goran J. Radosavljević and Nelu V. Blaž

Significant achievements in ferrite material processing enable developments of many ferrite devices with a wide range of power levels and working frequencies, which make demands…

Abstract

Purpose

Significant achievements in ferrite material processing enable developments of many ferrite devices with a wide range of power levels and working frequencies, which make demands for new characterization and modelling methods for ferrite materials and components. The purpose of this paper is to introduce a modelling and measurement procedure, which can be used for the characterization of two‐port ferrite components in high frequency range.

Design/methodology/approach

This paper presents a commercially available ferrite component (transformer) modelling and determination of its electrical parameters using in‐house developed software. The components are measured and characterized using a vector network analyzer E5071B and adaptation test fixture on PCB board. The parameters of electrical equivalent circuit of the ferrite transformer parameters are compared with values extracted out of measured scattering parameters.

Findings

A good agreement between modelled and extracted electrical parameters of the ferrite transformer is found. The modelled inductance curves have the same dependence versus frequency as extracted ones. That confirms the model validity in the wide frequency range.

Originality/value

In‐house developed software based on proposed model provides inclusion of the ferrite material dispersive characteristics, which dominantly determines high‐frequency behaviour of two‐port ferrite components. Developed software enables fast and accurate calculation of the ferrite transformer electrical parameters and its redesign in order to achieve the best performance for required application.

Details

Microelectronics International, vol. 29 no. 2
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 2 January 2007

Vandan Surve and Vijaya Puri

To study nonreciprocal effects in microstrip components due to ferrite thin film overlay.

Abstract

Purpose

To study nonreciprocal effects in microstrip components due to ferrite thin film overlay.

Design/methodology/approach

The possibility of obtaining non reciprocal characteristics in the X band microwave region in the absence of external magnetic field by a simple process of using Mg, Co, Zn ferrite thin films as in‐touch overlay over λ/2 microstrip rejection filter was investigated. Microstrip rejection filter is basically a reciprocal component. The ferrite thin films were deposited by electroless plating.

Findings

It was found that frequency, pH and ferrite overlay material dependent changes occurred and differences in forward and reverse loss also observed, in some cases greater than 30 dB. Owing to the overlay the rejection properties of the filter is lost and there is an increase in insertion loss. The best non reciprocal effects are seen at higher frequencies. The presence of permeability related effects like magnetostatic modes interfering with the normal propagation of the microstrip circuits might be causing the changes in the circuits.

Originality/value

There is scope for true planarisation of ferrite‐based components by using the ferrite in thin film form as in‐touch overlay.

Details

Microelectronics International, vol. 24 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

Article
Publication date: 11 January 2011

A. Miszczyk and K. Darowicki

The purpose of this paper is to report the electrochemical verification of anticorrosive properties of NiZn ferrites as pigments in protective coatings and evaluation of their…

4278

Abstract

Purpose

The purpose of this paper is to report the electrochemical verification of anticorrosive properties of NiZn ferrites as pigments in protective coatings and evaluation of their microwave absorbing properties.

Design/methodology/approach

Ferrites, represented by formula NixZn(1−x)Fe2O4, where x=0, 0.2, 0.4, 0.6, 0.8, 1.0, were synthesized using a ceramic method. The samples of ferrites were examined by X‐ray diffraction and SEM. Immersion tests in ferrite extracts, combined with electrochemical tests using techniques such as polarization curves, linear polarization and electrochemical impedance spectroscopy (EIS) were involved to determine the protective action provided by the ferrites. Epoxy coatings containing 10 vol.% of the ferrite were investigated using EIS. Experimental verification is provided of the microwave attenuation capability of coatings containing the investigated ferrites. Reflection loss, measured in the frequency range of 6.5‐15 GHz, exhibited maximum attenuation at a level of 8‐16 dB.

Findings

The results obtained suggest that NiZn ferrites possess active anticorrosive properties and support inhibition of the cathodic reaction by scale deposition at the metal substrate in an alkaline environment created by the pigments and the cathodic reaction. Additionally, they can serve as a microwave suppressor.

Practical implications

NiZn pigments can be used in coatings to serve simultaneously as an active anticorrosion, non‐toxic pigment and a material protecting against electromagnetic interference problems.

Originality/value

The paper provides information regarding the anticorrosive properties of NiZn ferrites as pigments for protective coatings and also microwave absorbing materials. An attempt was made to elucidate the potential mechanism of anticorrosive action of these pigments.

Details

Anti-Corrosion Methods and Materials, vol. 58 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 1 April 2005

Jaroslav Mackerle

Ceramic materials and glasses have become important in modern industry as well as in the consumer environment. Heat resistant ceramics are used in the metal forming processes or…

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Abstract

Purpose

Ceramic materials and glasses have become important in modern industry as well as in the consumer environment. Heat resistant ceramics are used in the metal forming processes or as welding and brazing fixtures, etc. Ceramic materials are frequently used in industries where a wear and chemical resistance are required criteria (seals, liners, grinding wheels, machining tools, etc.). Electrical, magnetic and optical properties of ceramic materials are important in electrical and electronic industries where these materials are used as sensors and actuators, integrated circuits, piezoelectric transducers, ultrasonic devices, microwave devices, magnetic tapes, and in other applications. A significant amount of literature is available on the finite element modelling (FEM) of ceramics and glass. This paper gives a listing of these published papers and is a continuation of the author's bibliography entitled “Finite element modelling of ceramics and glass” and published in Engineering Computations, Vol. 16, 1999, pp. 510‐71 for the period 1977‐1998.

Design/methodology/approach

The form of the paper is a bibliography. Listed references have been retrieved from the author's database, MAKEBASE. Also Compendex has been checked. The period is 1998‐2004.

Findings

Provides a listing of 1,432 references. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.

Originality/value

This paper makes it easy for professionals working with the numerical methods with applications to ceramics and glasses to be up‐to‐date in an effective way.

Details

Engineering Computations, vol. 22 no. 3
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 10 May 2019

Yahia Achour and Jacek Starzyński

This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of…

Abstract

Purpose

This paper aims to describe a new concept of transformer based on the displacement current. The paper shows how this idea can be translated into reality and presents an example of a working design.

Design/methodology/approach

The authors replace the primary winding of the transformer with a capacitor. The displacement current between the capacitor plates induces a magnetic flux in the core. This flux in turn induces electromotive force in the classical secondary winding.

Findings

The basic mathematical aspects illustrated by results obtained from a simulation developed using a commercial software ANSYS-HFSS are given. The saturation of the magnetic core due to the applied high-frequency range is investigated and simulated using a finite difference time domain code implemented in MATLAB. A prototype transformer was built and tested; the obtained results confirm the previous ones from simulations.

Originality/value

A new concept of the single winding transformer was used as a pulse forming circuit.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 38 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 January 2016

R.P. Pawar and Vijaya Puri

– This paper aims to study the structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) thick-film ceramics.

Abstract

Purpose

This paper aims to study the structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) thick-film ceramics.

Design/methodology/approach

The thick films of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0) on the alumina substrate have been delineated using screen printing technique. The structural analysis was carried out using an X-ray diffraction method and scanning electron microscopy. The direct current (DC) electrical resistivity is measured using a two-probe method. Microwave absorption was studied in the 8-18 GHz frequency range by using the Waveguide Reflectometer Method. The permittivity and permeability in the 8-18 GHz frequency range were measured by using Voltage Standing Wave Ratio slotted section method.

Findings

The thick films have orthorhombic perovskite structure with dominant (020) plane. By using first-principle calculation method, theoretical and experimental lattice parameter and cell volume of (Sr0.6Ca0.4) (CoyMn1−y) O3 are matched with each other. The cobalt content changes the morphology from plates to needles. The DC electrical resistivity increases with increase in Co content and decreases with increase in temperature. (Sr0.6Ca0.4) (CoyMn1−y) O3 thick film shows 75 per cent microwave absorption both in the X band and Ku band. The microwave permittivity and permeability decreases with increase in frequency and Co content.

Originality/value

Structural, electrical and microwave properties of (Sr0.6Ca0.4) (CoyMn1−y) O3 (0.2 ≤ y ≤ 1.0). Thick film ceramics on alumina substrate is reported for the first time.

Details

Microelectronics International, vol. 33 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

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