Preparation of nickel aluminate spinel by microwave heating

Amini, Mostafa M.; Torkian, Leila

doi:10.1016/s0167-577x(02)00845-5

Cited by 30 publications

(4 citation statements)

References 15 publications

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“…Several techniques can be used for the production of nickel aluminate spinel, with the most common being the combustion method [ 15 ], chemical co-precipitation [ 16 , 17 ], microwave heating from a coprecipitated mixture of nickel and aluminum hydroxides precursor [ 18 ], the sol–gel auto combustion method and calcination [ 19 ], or the simple sol–gel method and calcination [ 20 ]. All of these methods result in pure or doped NiAl 2 O 4 ceramic materials, and to a lesser extent, the Ni-NiAl 2 O 4 cermet materials, which are very useful for anode technologies.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

et al. 2022

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To obtain highly homogeneous cobalt–nickel aluminate spinels with small crystallite sizes, CoNiAl alloy thin films were primarily deposited using Laser-induced Thermionic Vacuum Arc (LTVA) as a versatile method for performing processing of multiple materials, such as alloy/composite thin films, at a nanometric scale. Following thermal annealing in air, the CoNiAl metallic thin films were transformed into ceramic oxidic (Co,Ni)Al2O4 with controlled composition and crystallinity suitable for thermal stability and chemical resistance devices. Structural analysis revealed the formation of (Co,Ni)Al2O4 from the amorphous CoNiAl alloys. The mean crystallite size of the spinels was around 15 nm. Thermal annealing induces a densification process, increasing the film thickness together with the migration process of the aluminum toward the surface of the samples. The sheet resistance changed drastically from 200–240 Ω/sq to more than 106 Ω/sq, revealing a step-by-step conversion of the metallic character of the thin film to a dielectric oxidic structure. These cermet materials can be used as inert anodes for the solid oxide fuel cells (SOFCs), which require not only high stability with respect to oxidizing gases such as oxygen, but also good electrical conductivity. These combination metal–ceramics are known as bi-layer anodes. By controlling the crystallite size and the interplay between the oxide/metal composite, a balance between stability and electrical conductivity can be achieved.

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Section: Introductionmentioning

confidence: 99%

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

et al. 2022

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“…But the dielectric permittivity of nanostructured materials falls below those for bulk materials in high-frequency regions, which restricts its explored applications in high-frequency devices [13]. Researchers used several synthesis techniques for synthesis of nano to bulk forms such as solid-state techniques [14], sol-gel [15], sonochemical [16], microwave [17], mechano-chemical synthesis [18] and one-pot synthesis [19] and many more. We have preferred solid-state synthesis process due to higher productivity, low cost and better filling properties (structural, electrical, magnetic, optical etc) in this method, which is more apparent.…”

Section: Introductionmentioning

confidence: 99%

Non-overlapping small polaron tunneling conduction coupled dielectric relaxation in weak ferromagnetic NiAl₂O₄

Karmakar

Behera

2019

J. Phys.: Condens. Matter

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The inverse spinel nickel aluminate micro-particles was successfully synthesized via solid-state synthesis techniques. The single phase cubic structure with space group Fd3m of the as-prepared sample was entrenched from Rietveld refinement of x-ray diffraction pattern. In addition, the photoluminescence (PL) and FTIR spectra were also performed to give strong evidence of its pure phase formation. The narrow hysteresis m–h loop and UV-DRS spectra at room temperature demonstrate its weak ferromagnetic and semiconducting nature with saturation magnetization 64.96 × 10−3 emu gm−1 and direct optical band gap 2.03 eV respectively. The high-resolution FESEM micrographs and EDS elemental analysis exhibit its grain growth in µm range (217 µm) and presence of elemental compound Ni, Al and O respectively. The electrical transport properties were accomplished by complex impedance spectroscopy as a function of frequency (100 Hz–1 MHz) with the evolution of high temperature (300 °C–500 °C). The Nyquist plots (Z″ versus Z′) were well fitted with an equivalent circuit model (QR) (QR) consisting of a series combination of intra and inter-granular contribution. Furthermore, the imaginary modulus spectra were also fitted with Kohlrausch–Williams–Watts (KWW) function, which represents two thermally activated peaks of grain and grain boundary effects. The low-frequency dispersive ac conductivity was elucidated using the following equation: . The increasing nature of temperature dependent frequency exponent (n) suggests the quantum mechanical tunneling: non-overlapping small polaron tunneling (NSPT) concept for conduction mechanism. In low-frequency region, the lattice and charge carrier polarization simultaneously contribute in dielectric permittivity.

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“…The inverse spinel structure shows ferromagnetic behavior and if synthesized as nano crystalline, it has unique potential application in high-density magnetic recording, microwave devices and magnetic fluids [7]. NiAl 2 O 4 can be prepared by different methods such as solid-state reaction [8], impregnation [9], co-precipitation [10], sol-gel [11] and microwave [12]. Formation of NiAl 2 O 4 by solid state reaction according to Eq (1) involves the sintering of the mixture of metal oxides at high temperature [8].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Nanostructured Nickel Aluminate Formation during Mechano-Chemical Recycling of Spent NiO/Al<sub>2</sub>O<sub>3</sub> Catalyst

Mohammad

Sheibani

Rashchi

et al. 2011

AMR

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In this research, use of mechanical alloying method, as a new and effective route for the recycling of spent NiO/Al2O3catalyst to nanostructured nickel aluminate spinel was investigated. Samples were characterized using different techniques such as X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). It was found that the formation of NiAl2O4was started between 15 to 20 hours of milling and completed after 60 hours. The final particles had relatively spherical shape with the size range of 5-50 nm.

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Preparation of nickel aluminate spinel by microwave heating

Cited by 30 publications

References 15 publications

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

Non-overlapping small polaron tunneling conduction coupled dielectric relaxation in weak ferromagnetic NiAl₂O₄

Characterization of Nanostructured Nickel Aluminate Formation during Mechano-Chemical Recycling of Spent NiO/Al<sub>2</sub>O<sub>3</sub> Catalyst

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Preparation of nickel aluminate spinel by microwave heating

Cited by 30 publications

References 15 publications

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

Synthesis of Cobalt–Nickel Aluminate Spinels Using the Laser-Induced Thermionic Vacuum Arc Method and Thermal Annealing Processes

Non-overlapping small polaron tunneling conduction coupled dielectric relaxation in weak ferromagnetic NiAl2O4

Characterization of Nanostructured Nickel Aluminate Formation during Mechano-Chemical Recycling of Spent NiO/Al<sub>2</sub>O<sub>3</sub> Catalyst

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Non-overlapping small polaron tunneling conduction coupled dielectric relaxation in weak ferromagnetic NiAl₂O₄