AUCTORES
Review Article
*Corresponding Author: N.Varalaxmi, Department of Physics,University College, Kakatiya University, Warangal-506009,Telangana State, INDIA
Citation: N.Varalaxmi, (2019) Review on the importance of material synthesis of nicuzn-mgcuzn ferrite materials for various applications. J. International Journal of Materials Science and Engineering, 1(1): Doi: 10.31579/ ijme.2019/002
Copyright: © 2019. N.Varalaxmi,This is an open-access article distributed under the terms of The Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Received: 01 November 2019 | Accepted: 10 October 2019 | Published: 23 October 2019
Keywords: multilayer chip inductors; miniaturization of components; ferrite materials; electrical and magnetic properties; surface mounting devices etc.
Because of the rapid development of technology newly improved techniques are replacing the older ones. Miniaturization of electronic components have great demand since last few decades. Due to their high electrical resitivities and for other efficient properties, ferrites have attracted the potential researchers due to their versatile applications in various fields, especially in the field of electronic industrial applications, also production of ferrites will increase as their applications become more diverse. Ferrites are used in the fabrication of multilayer chip inductors (MLCIs) as surface mounting devices for micro miniaturization of various electronics devices. Recently, surface mounting devices have been rapidly developed for micro-indcutor applications,which have great demand in electronic applications. Dominant materials for MLCIs are soft ferrites materials. This brief review outlines the work being carried out on the various synthesis of NiCuzn-MgCuzn ferrites materials for their various applications.
Research area plays major role to develop the new activities in science and technology. The concept of miniaturization was developed originally by a word called surface mounting. Originally surface mounting was called as "planar mounting". "Surface-mount" refers to a methodology of manufacturing, which distinguishes the components, technique, and machines used in manufacturing and different terminology will be used, when it is referring to the different aspect of the methods. In 1960s, surface-mount technology was developed and became widely used in the 1980s, as a trend in the industry. it has largely replaced a traditional through-hole technique construction method of fitting of the components with the leads into the holes in the circuit board, with the surface mounted technology (SMT) using surface mounted devices (SMD). Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted (or) assembled (or) placed directly onto the surface of printed circuit boards (PCBs). The SMT technique opens advantages and new applications through miniaturizing of the components and increasing of reliability. Both technologies can be used on the same board for components not suited to surface mounting such as large transformers and heatsinked power semiconductors
1.1 Importance of miniaturization:
Miniaturization is important because improved chip packaging led to creating newest markets by enabling new applications. Personal communications is a developing major consumer market created by mimiaturization. Higher speed, lower cost and greater density are the inherent advantages of miniaturization. It also reduces the cost of electronics by packing more functionality into a smaller or same sized device.
1.2. Miniaturization process of SMDS:
The SMD is not a “new technique”, it is only a miniaturisation of the components. But this component requires a different processing technology. It is an electronic device, so made is called a surface-mount device (SMD). SMDs which means a trend to continue many new components available such as active, passive, electronic components (or) electromechanical components without conventional connecting wires as shown in Fig.1. Most of the SMD components available during 1998 ends with pin-outs, SMD/classic and classic/SMD.
The tendency to miniaturize electronic components began in the 1990s. Rapid progress also occurred in surface-mounting technology, and attempts have been made to accomplish high density, by incorporating ferrite inductors into a printed circuit board. A ferrite inductor is made up of ferri magnetic material or ferro magnetic material known as “magnetic core” consisting mainly powdered iron, which posses high permeability and and high electrical resistivities which are useful for transformers, recording heads, inductors and generators etc., This has, as a result, allowed development of various types of multilayer ferrite chip inductors [1]. Mostly ferrite magnebtic materials are used in radios for tunning a inductor. Coil has to wound around the ferrite core so that inductance can be adjusted through the coil when coil changes the flux. Generally, this has a length of 10 mm and a width of 0.5 mm, to be used in television receivers, video equipment, headphone stereos, hard disk device systems, personal computers, cordless telephones, automobiles parts etc. Multilayer ferrite chip inductors are manufactured using the thick film printing method, and the latest chip inductors are successfully constructed as a single monolithic structure that combines the inductor with other passive elements such as capacitors and resistors.
An improved multilayer chip inductor comprises a plurality of sheets which are multilayered, which means is composed of an upper cover and a lower cover sheet and several sheets multilatyered between them; these sheets can be selected as magnetic or non-magnetic material according to design requirements. By making them multilayered and using low- temperature co-fired ceramic (LTCC) technology an unshielded area is left on the packaging surface to result in open magnetic force such that current carrying capability of the chip inductor can be improved. The main feature is that the internal layer of the sheet is made of magnetic material (or non-magnetic material) and non-magnetic material (or magnetic material) as shown in Fig.2.
Microminiaturization of electronic circuits especially in the fields of mobile communication and information technology demands the fabrication of electronic devices of very small size [2]. Recently, the surface mounting technology demands the electronic components in a miniature form and surface mounting devices (SMD) have been rapidly developing for various electronic applications such as micro-inductor applications. Chip inductors are one of the passive surface mounting devices (SMD). They are important components for the latest electronic products such as cellular phones, video cameras, notebook computers, wireless communications, laptop computers, hard and floppy drives etc., which need to have qualities of small dimensions, light weight and better functions [3-4]. To satisfy these demands few ferrites materials are best suited for these applications as Surface Mounting Device (SMD).
1.3. Wire wound inductors:
Dram type inductors are wire wound and moulded to a resin to withstand against moisture and mechanical shocks. During hardening, the resin shrinks and applies compressive stress to the core material, which influences the core material substantially. The shrinkage of resin produces very high stress on the core and as a consequence, the inductance decreases [8-9]. This decrease in inductance results in much lower values of the moulded inductor and thus poses a problem in mass production. The initial permeability of ferrite is a very sensitive property to the external stress.
The present chip inductor features make the miniaturization process very easy. The flux is entirely free from leakage because the coil is shielded with the ferrite material. Hence it is expected that the demand for the chip inductors will increase in future.
Silver is generally used as the material for the internal electrode of the multilayer chip inductors due to its low resistivity, resulting in the components with high-quality factor (Q) [10]. In addition to this, Ag paste is commercially available at lower cost than Ag-Pd paste. Since the melting point of silver is 961ºC, the sintering temperature of ferrite which is used for the manufacture of chip inductor should be below 950 ºC. This is because of the need to prevent Ag diffusion into the ferrite that would increase the resistivity of the internal conductor. Further, the segregation of Cu2+ from the ferrite induced by the diffused Ag can be avoided and thus no deterioration in magnetic properties of the material. In order to overcome these problems, MgCuZn ferrites were found to be suitable [11-13]. Normally, MgCuZn ferrites were sintered at temperatures higher than 1100 ºC [11-12, 14]. In order to use these ferrites in multilayer chip components, the sintering temperature must not be more than the melting point of silver.
With the rapid development and advancement of mobile communication and information technology, the electronic components with small size, high efficiency, and low cost are urgently needed [15]. Multilayer chip inductors (MLCIs) as a key component of electronic devices confront new challenges. Better magnetic properties, especially high initial permeability are required for reducing the number layers of multilayer chip inductors. At present NiCuZn ferrites have been used extensively for the production of the MLCI [16] but they are highly stress sensitive.
1.4. Suitable ferrite materials
In search of suitable ferrite materials for microinductor applications, a review has been made, in the present work, hence the author has under taken this review and outlines the work being carried out, these studies revealed the development of new materials for the multilayer chip inductors by concluding that these ferrites possess good electromagnetic properties, can be exploited as core material for microinductor applications and DC-DC transformer core applications.
2.1. Materials for microinductor applications:
The summary of research work carried out by various researchers for microindcutors applications is represented in Table. 1. Penchal Reddy et.al. [17] carried out the work on structural, electrical and magnetic characterization of NiCuZn spinel ferrites with chemical formulae Ni0.35Cu0.05Zn0.60Fe1.98O4_δ prepared by microwave sintering (MS) method, and the results were compared with the properties of materials prepared by conventional double sintering method (CS). The essential difference in the microwave and conventional sintering process is in the heating mechanism. Varalaxmi and Sivakumar reported [18] a comparative study on structural, magnetic, electric properties and stress sensitivity of the Ni0.175Mg0.125Cu0.15Zn0.55Fe2O4 with equimolar nano composite ferrite 0.5((Ni0.35Cu0.05Zn0.6Fe2O4)+(Mg0.25Cu0.25Zn0.5Fe2O4)) prepared by conventional double sintering technique, with a view to develop a ferrite composition for its use as core material for microinductor applications.
Penchal Reddy et.al. [19] investigated microwave sintering of nickel ferrites nanoparticles processed via sol-gel method. Low-temperature synthesis of iron deficient Ni-Cu-Zn ferrites for multilayer chip inductors using the microwave sintering technique studies was carried out by Penchal Reddy et.al. [20]. Influence of copper substitution on magnetic and electrical properties of MgCuZn ferrite with chemical formulae Mg0.50-xCuxZn0.50Fe2O4 prepared by microwave sintering method were investigated by Penchal Reddy et.al. [21]. Microwave sintering of high-permeability MgCuZn ferrite at low sintering temperatures suitable for microinductor applications with the composition Mg0.40Cu0.10Zn0.50Fe1.95O4-δ was prepared by microwave sintering and conventional sintering techniques by Penchal Reddy et.al., [22].
Penchal Reddy et.al. [27] successfully synthesized cobalt substituted manganese nanocrystalline spinel ferrites having general formula CoxMn1-xFe2O4 (0 ≤ x ≤ 1:0) using the hydrothermal method. Effects of sintering temperature on the structural and magnetic properties of Mn0.50Zn0.50Cr0.4Fe1.6O4 which were synthesized by combustion method and sintered at various temperatures (1250, 1300 and 1350ºC) has been discussed by Alam et.al. [28].
Sintering behavior, microstructure and electromagnetic properties of NiCuZn ferrites doped with B2O3 sintered in the temperature range of 850–9500C were investigated by Shen et.al. [29]. The thermolysis of copper ferrimalonate Cu3[Fe(CH2C2O4)3]2·9H2O has been investigated up to 1073 K in flowing air atmosphere employing various physicochemical techniques by Singh et.al [30] and concluded that the temperature of ferrite formation (623 K) is considerably lower than that of conventional ceramic method (>1273 K). Cobalt ferrite materials with different concentrations of manganese additions have been prepared by the conventional ceramic technique by [31]. Varalaxmi and Sivakumar [32] carried out the studies on the development of a stress insensitive MgCuZn-NiCuZn composite ferrite useful for microinductors applications and concluded that composite ferrites are useful for microinductor applications. Batoo and Ansari [33] have investigated ferrite nanoparticles of composition Ni0.7-xZnxCu0.3Fe2O4 (0.0 ≤ x ≤ 0.2, x = 0.05) which were synthesized through auto-combustion method. These studies were conducted for structural properties investigation. Zahi et.al. [34] carried out the studies on the Ni-Zn ferrite powder with generic formula Ni0.3Zn0.7Fe2O4 which was synthesized by the sol-gel route using metal acetates at low temperatures.
Dimiri et.al [35] studied powders of Ni0.6−xCuxZn0.4Fe2O4, within the range 0≤x≤0.4, prepared by the citrate precursor method to investigate its structural, dielectric and magnetic properties. Kaczkowski [36] carried out the studies on stress sensitivity in Ni-Mn, Ni-Mn-Co and Ni-Mn-Co-Cu ferrites and observed greatest stress sensitivity for ferrites with the smallest magnetocrystalline anisotrophy containing a maximum of cobalt ions. Szewczyk and Bie´nkowski [37] presented their results of the investigation of the stress sensitivity of the fluxgate sensor with amorphous alloy (CoFe)89(MnMoSiB)11 (Vitrovac 6150F) ring core.
The possibility of utilizing the high permeability magnetic materials in the construction of magnetoelastic stress and force sensors studies were carried out by Szewczyk and Bie´nkowski [38]. Yan and Hu [39] carried out studies on (Ni0.20Zn0.60Cu0.20)Fe1.98O4 ferrite sintered using microwave sintering and conventional sintering technique and observed that microwave sintering technique has much shorter sintering time compared with conventional sintering technique. Nakamura et.al [40] investigated a multi-layer chip inductor (MLCI) which is prepared with the green-sheet technique, using polycrystalline Li-Zn-Cu-Mn ferrite. The complex impedance spectra were evaluated with the help of numerical calculations, and the experimentally obtained complex impedance spectra of the MCI component were quite well reproduced by the calculation in the case of Li-Zn-Cu-Mn ferrite but not in the case of Ni-Zn-Cu ferrite. The magneto-striction coefficient, and the magnetostriction effect was negligible in the MCI component using Li-Zn-Cu-Mn ferrite. Simulation and design of micro inductor for in wireless sensor network eletrcomagnetic energy scavenging at low-frequency studies were carried out by Zhang et.al [41]. Roy and Bera [42] carried out studies on effect of Mg substitution on electromagnetic properties of (Ni0.25Cu0.20Zn0.55) Fe2O4 ferrite synthesized through nitrate-citrate auto-combustion method.
Madhuri et.al., [43] studied stoichiometric and 1 wt% lead borosilicate (PBS) glass added MgCuZn ferrite with the general formula Mg0.5CuxZn0.5-xFe2O4 synthesized by microwave sintering technique. Penchal Reddy et.al. [44] has carried out the studies on low temperature microwave sintered NiCuZn and MgCuZn ferrites with chemical composition Ni0.35Cu0.05Zn0.60Fe2O4 and Mg0.35Cu0.05Zn0.60Fe2O4, which were synthesized by conventional mixed oxide method.
Studies were carried out on Ni0.35Cu0.05Zn0.60Fe1.98O4−δ ferrite prepared by microwave sintering (MS) method and compared with the conventional sintering method (CS) by Penchal Reddy et.al [45]. In order to study structural, magnetic and electrical properties suitable for MLCI applications polycrystalline NiCuZn soft ferrites with stoichiometric iron were prepared by a novel microwave sintering method [46]. Penchal Reddy et.al [47] investigated a NiCuZn ferrite with composition
(Ni0.42+