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Article
Publication date: 28 May 2021

Fan Bao, Kaiyu Zhang, Zhengrong Zhou, Wenli Zhang, Xiao Cai and Lin Zhang

The purpose of this paper is to demonstrate the effect of δ-ferrite on the susceptibility to hydrogen embrittlement of type 304 stainless steel in hydrogen gas environment.

Abstract

Purpose

The purpose of this paper is to demonstrate the effect of δ-ferrite on the susceptibility to hydrogen embrittlement of type 304 stainless steel in hydrogen gas environment.

Design/methodology/approach

The mechanical properties of as-received and solution-treated specimens were investigated by the test of tensile and fatigue crack growth (FCG) in 5 MPa argon and hydrogen.

Findings

The presence of δ-ferrite reduced the relative elongation and the relative reduction area (H2/Ar) of 304 stainless steel, indicating that δ-ferrite increased the susceptibility of hydrogen embrittlement in 304 stainless steel. Moreover, δ-ferrite promoted the fatigue crack initiation and propagation at the interface between δ-ferrite and austenite. The FCG tests were used to investigate the effect of δ-ferrite on the FCG rate in hydrogen gas environment, and it was found that δ-ferrite accelerated the FCG rate, which was attributed to rapid diffusion and accumulation of hydrogen around the fatigue crack tip through δ-ferrite in high-pressure hydrogen gas environment.

Originality/value

The dependence of the susceptibility to hydrogen embrittlement on δ-ferrite was first investigated in type 304 steel in hydrogen environment with high pressures, which provided the basis for the design and development of a high strength, hydrogen embrittle-resistant austenitic stainless steel.

Details

Anti-Corrosion Methods and Materials, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0003-5599

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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…

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

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Article
Publication date: 5 January 2015

N. Patil, N.B. Velhal, R. Pawar and Vijaya Puri

The purpose of this article is to study the effect of ferrite content on electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 …

Abstract

Purpose

The purpose of this article is to study the effect of ferrite content on electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 − y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) thick films on alumina.

Design/methodology/approach

Thick films of ferrite–ferroelectric composite on alumina substrate have been delineated using screen printing technique. The structural analysis was carried out using X-ray diffraction method and scanning electron microscopy. The DC electrical resistivity was measured using the two-probe method. The magnetic measurement was carried out using a vibrating sample magnetometer. Microwave absorption was studied in the 8-18 GHz frequency range by using the vector network analyzer (N5230A). The permittivity in the 8-18 GHz frequency range was measured by using voltage standing wave ratio slotted section method.

Findings

The formation of two individual ferrite–ferroelectric phases in composite thick films was confirmed by the X-ray diffraction patterns. The scanning electron microscope morphologies show the growth of cobalt-substituted nickel cadmium ferrite grains which are well dispersed in lead zirconium titanate matrix. The DC electrical resistivity increases with increase in ferrite content and decreases with increase in temperature. The present ferrite shows ferromagnetic nature and it increases saturation magnetization and coercivity of the composite thick films. Tuning properties are observed in the Ku-band and broadband X-band microwave absorption is observed in the composite thick films. The imaginary part of permittivity increases with an increase in ferrite content, which increases microwave absorption. The real part of microwave permittivity varied from 17 to around 22 with an increase in ferrite content and it decreases with frequency. The microwave conductivity, which increases with an increase in ferrite content, reveals the loss of polaron conduction, which supports the dielectric loss in the microwave region.

Originality/value

Electric, magnetic and microwave properties of screen-printed y(Ni0.4Co0.2Cd0.4Fe2O4) + (1 − y)Pb(Zr0.52Ti0.48)O3 (y = 0.0, 0.15, 0.30, 0.45, 1.0) composite thick films on alumina substrate is reported for the first time.

Details

Microelectronics International, vol. 32 no. 1
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 December 2005

F.F. Abdel‐Mohsen and H.S. Emira

To prepare of fine particle size magnesium ferrite pigments by sol‐gel method.

Abstract

Purpose

To prepare of fine particle size magnesium ferrite pigments by sol‐gel method.

Design/methodology/approach

Different magnesium ferrite pigments with stoichiometric ratios were prepared by sol‐gel and dispersion methods. The characterisation of magnesium ferrite pigments were based on X‐ray diffraction, transmission electron microscope, particle size distribution, thermal and magnetometric analyses.

Findings

The type of polymer and the starting inorganic materials (oxides or salts) have a significant effect on the properties of the magnesium ferrite pigments prepared.

Research limitations/implications

The magnesium ferrite pigments, prepared and used in the work reported here were synthesised from magnesium and iron oxides, oxalates and chlorides. Urea formaldehyde resin and acrylic polymer were used as the dispersing media. Various other materials, e.g. carboxymethyl cellulose, ethoxy methyl cellulose, polyvinylalcohol and 2‐hydroxyethyl methacrylate and polyacrylamide can also be used to achieve similar effect.

Practical implications

The sol‐gel method provided a fine particle size and different particle shapes. Therefore, the method of preparation could be used to produce fibres, films and monoliths.

Originality/value

The magnesium ferrite pigments prepared could be use in numerous paints for steel protection.

Details

Pigment & Resin Technology, vol. 34 no. 6
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 3 June 2020

Mayya Ziganshina, Sergey Stepin, Sergey Karandashov and Veronika Mendelson

The purpose of this paper is to search for toxic anticorrosive pigments’ substitute in protective coatings is one of the important tasks that the specialists in the field…

Abstract

Purpose

The purpose of this paper is to search for toxic anticorrosive pigments’ substitute in protective coatings is one of the important tasks that the specialists in the field of steel corrosion face.

Design/methodology/approach

One of the ways to solve the problem of metal corrosion is to use complex oxides as pigments, which are characterized as low-toxic compounds and possess the ability to inhibit corrosion.

Findings

In the production of ferrites, it is possible to use production waste as raw material, and that makes it possible to reduce the price of the resulting product and solve environmental problems simultaneously.

Originality/value

Permanent growth of world production is accompanied by the increasing environment corrosiveness, associated with the intensification of air, water basin and soil pollution by industrial waste. This, as well as the continuously increasing operated metal stock, has recently made the tendency of metals’ total loss from corrosion steadily increasing. All of this points to the importance of studying corrosion processes and the systematic and effective fight against metal corrosion.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 27 June 2008

A. Kalendová and D. Veselý

The purpose of this paper is to synthesize anticorrosion pigments ZnFe2O4 from diverse raw materials of various shapes and size of primary particles.

Abstract

Purpose

The purpose of this paper is to synthesize anticorrosion pigments ZnFe2O4 from diverse raw materials of various shapes and size of primary particles.

Design/methodology/approach

Anticorrosion pigments were synthesized through a high‐temperature process during a solid phase. Zinc ferrites were prepared from hematite (α‐Fe2O3), goethite (α‐FeO.OH), magnetite (Fe3O4), and specularite (Fe2O3) entering into reaction with zinc oxide at temperatures ranging from 600 up to 1,100°C. The nature of the initial raw material, primarily the shape of its particles, affects the shape of the particles of the synthesized zinc ferrite. The formulated zinc ferrites had a rod‐shape, lamellar, and/or isometric shape. The shape of the particles of synthesized zinc ferrites was studied with regard to its effects on the mechanical and corrosion resistance of organic coatings. The obtained pigments were characterized by means of X‐ray diffraction analysis and scanning electron microscopy. The synthesized anticorrosion pigments were used to prepare epoxy coatings and water‐borne styrene‐acrylate coatings that were subjected to post‐application tests for physical‐mechanical properties and anticorrosion properties.

Findings

The shape of the particles was identified in the synthesized pigments. X‐ray diffraction analysis revealed the degree of precipitation and lattice parameters. All of the synthesized pigments had good anticorrosion efficiency in an epoxy and in styrene‐acrylate coatings. Compared with a commercially used anticorrosion pigment, their protective power in coatings was demonstrably stronger.

Practical implications

The synthesized pigments can be used conveniently in coatings protecting metal bases against corrosion.

Originality/value

The synthesis of zinc ferrites with different particle shapes for applications in anticorrosion coatings provides a new way of protecting metals against corrosion. Of benefit is the fact that the synthesized pigments do not contain any environmentally harmful substances.

Details

Anti-Corrosion Methods and Materials, vol. 55 no. 4
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 23 March 2010

Nivin M. Ahmed and Mohamed M. Selim

The purpose of this paper is to determine a new easy route to obtain high performance and economic anticorrosive hybrid pigments based on kaolin and ferrite. The new route…

Abstract

Purpose

The purpose of this paper is to determine a new easy route to obtain high performance and economic anticorrosive hybrid pigments based on kaolin and ferrite. The new route is based on depositing a surface layer of an expensive efficient anticorrosive pigment (ferrite) on a bulk of cheap extender pigment (kaolin). The combination of these pigments can add improved properties to the new pigment different from each of its individual components. These improved properties lead to imparting new properties to paint films containing these prepared pigments.

Design/methodology/approach

The new prepared hybrid pigments contain different concentrations of deposited ferrite on kaolin surface, are determined using X‐ray fluorescence analysis to estimate the concentration of each element in the pigments. The pigments are characterised using different spectro‐photometric and analytical methods to prove the deposition of the shell layer and elucidate the structure of their particles. Then, they are incorporated in anticorrosive paint formulations, where their presence in these formulations is between 50 and 75 per cent of the total pigments in the paint formula. A model of the mechanism of protection to the metal substrate is presented.

Findings

The results show that the presence of these hybrid pigments imparts excellent corrosion protection to steel substrates, in spite of their different concentrations and loadings in the paint films.

Practical implications

These pigments can be applied in other polymer composites, e.g. rubber and plastics as filler and reinforcing agent.

Originality/value

Prepared pigments are eco‐friendly and can replace other hazardous pigments (e.g. chromates) – also it can replace original ferrite pigments. These pigments can compensate for the presence of other known pigments in markets successfully. The main advantage of these pigments is that they combine both the properties of their counter‐parts, and they are of lower cost than the original inhibitive pigment (ferrite). Also, they can be applied in other industries other than paints, e.g. paper, rubber and plastics composites.

Details

Pigment & Resin Technology, vol. 39 no. 2
Type: Research Article
ISSN: 0369-9420

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Article
Publication date: 1 September 2006

Mirjana Damnjanović, Goran Stojanović, Ljiljana Živanov and Vladan Desnica

Present 3D electromagnetic simulators have high accuracy, but they are time and memory expensive. Because of that, fast and simple expression for impedance is also…

Abstract

Purpose

Present 3D electromagnetic simulators have high accuracy, but they are time and memory expensive. Because of that, fast and simple expression for impedance is also necessary for initial inductor design. In this paper new efficient method for total impedance calculation of ferrite electromagnetic interference (EMI) suppressor is given. By using an algorithm, it is possible to predict correctly all variations of electrical characteristics introduced by varying geometry parameters of EMI suppressor.

Design/methodology/approach

The starting point for calculation of electrical characteristics of EMI suppressor is Greenhouse theory. Greenhouse decomposed inductor into its constituent segments. Basically, all segments of conductive layer are divided into parallel filaments having small, rectangular cross sections. The self‐ and mutual‐inductance were calculated using the concept of partial inductance. Total impedance of EMI suppressor is calculated taking care of dimension of chip size, material that are used and geometry of conductive layer.

Findings

The Simulator for Planar Inductive Structures (SPIS™) simulates effects of ferrite materials and geometrical parameters of planar inductive structures. With proposed software tool, designers can predict performance parameters quickly and easily before costly prototypes are built. SPIS™ software offers substantially reduced time to market, and increases device performance. The computed impedances, given by our software tool are compared with measured data and very good agreement was found.

Practical implications

Applied flexible efficient methods for impedance calculation of EMI suppressor are able to significantly increase the speed design of multilayer suppressors for universal series bus, low‐voltage differential signaling and in other high‐speed digital interfaces incorporated in notebooks and personal computers, digital cameras and scanners. Also, ferrite suppressors have been successfully employed for attenuating EMI in switching power supplies, electronic ignition systems, garage door openers, etc.

Originality/value

The paper presents realized structures of ferrite EMI suppressors. New geometries of conductive layer are proposed. In addition, using simple model of inductor, the paper develops a CAD simulation tool SPIS™ for calculation of electrical characteristics of EMI suppressors with different geometry of conductive layer.

Details

Microelectronics International, vol. 23 no. 3
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 1 August 1997

O.S. Aleksić, P.M. Nikolić, D. Vasiljević‐Radović, Luković and S. Durić

A variety of thick film planar inductors, designed forapplications in the HF range, were printed from conductive PdAg and NiFe2O4 ferrite paste on alumina substrate. Pure…

Abstract

A variety of thick film planar inductors, designed for applications in the HF range, were printed from conductive PdAg and NiFe2O4 ferrite paste on alumina substrate. Pure ferrite powder with a nanometric particle size was used in the NiFe2O4 paste preparation. The ferrite thick film layer characterisation was performed on small spirals, after which the following inductor planar geometries were tested together with ferrite layers: meanders, spirals, bispirals and solenoid in plane. Their impedance was analysed with an impedance analyser in the MHz‐GHz range. The results obtained were compared with the properties of the smallest cubic inductors and with the literature data for planar inductors (theoretical and practical). A comparison was made of the L geometries printed. It was observed that better utilisation of the thick ferrite layers was achieved on L geometries with equally distributed windings over the thick ferrite layers.

Details

Microelectronics International, vol. 14 no. 2
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 7 September 2015

Nivin M Ahmed, Walaa M. Abd El-Gawad, Elham A. Youssef and Eglal R. Souaya

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original…

Abstract

Purpose

The purpose of this paper is to present the preparation of core-shell ferrites/kaolin pigments and comparing their efficiency in protecting metal substrates to original ferrites which were also prepared. Core-shell structured particles are recently gaining lots of importance due to their exciting applications in different fields; these particles are constructed from cores and shells of different chemical compositions which show ultimately distinctive properties of varied materials different from their counterparts. The new core-shell pigment is based on shell of different ferrites that comprises only 10-20 per cent of the whole pigment on kaolin (cores) which is a cheap and abundant ore that comprises 80-90 per cent of the prepared pigment. The new pigments do not only comprise two different components, but they also contain pigment and extender in the same compound; their loadings in the paint formulations ranges from 50 and 75 per cent of the whole pigment. The work showed that these eco-friendly and cheap core-shell pigments are comparable in their efficiency to that of ferrites in protecting steel substrates.

Design/methodology/approach

The different ferrites and ferrites/kaolin pigments were characterized using different analytical and spectrophotometric techniques, such as X-ray fluorescence, X-ray diffraction (XRD), scanning electron microscopy/energy-dispersive X-ray (SEM/EDAX) and transmission electron microscopy (TEM). Evaluation of these pigments was done using international standard testing methods (ASTM). After evaluation, the pigments were incorporated in solvent-based paint formulations based on medium oil-modified soya-bean dehydrated castor oil alkyd resin. The physico-mechanical properties of dry films and their corrosion properties using accelerated laboratory test in 3.5 per cent NaCl for 28 days were determined.

Findings

The results of this work revealed that ferrite/kaolin core-shell pigments were close in their performance to that of the ferrite pigments in protection of steel, and at the same time, they verified good physico-mechanical properties.

Practical implications

Treated kaolin can be applied in many industries beside pigment manufacture and paint formulations; it can be applied as reinforcing filler in rubber, plastics and ceramic composites. Also, it is applied in paper filling, paper coatings and electrical insulation.

Originality/value

Ferrite and ferrite/kaolin are environmentally friendly and can replace other hazardous pigments (e.g. chromates) with almost the same quality in their performance; also, they can be used in industries other than paints, for example paper, rubber and plastics composites.

Details

Pigment & Resin Technology, vol. 44 no. 5
Type: Research Article
ISSN: 0369-9420

Keywords

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