Rare-earth (RE) doping can greatly enhance the voltage gradient of ZnO-based varistors, and their nonlinear coefficient, leakage current, energy absorption capability, through-current capability and residual voltage can also be improved to certain extent. In this review, the progress on RE-doped ZnO-based varistor materials in recent years was summarized. The mechanism of RE doping on the electrical performance of ZnO varistors was analyzed. The issues in exploring new ZnO-based varistor mate...

The magnetocaloric effect (MCE) achieved for La_0.7Sr_0.3MnO₃/Ta₂O₅ composites has been investigated. The maximum value of magnetic entropy change of La_0.7Sr_0.3MnO₃ composites is found to decrease slightly with the further increasing of Ta₂O₅ concentration. It is shown that La_0.7Sr_0.3MnO₃/Ta₂O₅ composites exhibit much more uniform m...

Titanium dioxide (TiO₂) was elaborated by four different thermal spray techniques—(i) plasma spraying using a water-stabilized torch, (ii) plasma spraying using a gas-stabilized torch, (iii) high velocity oxy–fuel gun, and (iv) oxy–acetylene flame. The porosity of the coatings was studied by optical microscopy, nano-structural features by scanning electron microscopy (SEM), phase composition by X-ray diffraction (XRD); the microhardness, surface roughness and wear resistance were e...

The ultrasonic micro-arc oxidation (UMAO) was used to fabricate ceramic coatings on magnesium alloy. UMAO coatings were produced at 60 W input ultrasonic. The effects of the ultrasound on the microstructure, phase composition, elemental distribution and corrosion resistance of the coatings were extensively investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX) and electrochemical workstation. The results showed that ultrasound i...

The polycrystalline samples of Bi_1-xPr_xFeO₃ (x = 0 and 0.1) were prepared by a solid-state reaction technique. Preliminary X-ray structural analysis has confirmed the formation of a single-phase compound. Studies of dielectric and impedance spectroscopy of the materials, carried out in wide frequency (1 kHz–1 MHz) and temperature (25–400 ℃) ranges, have provided many interesting results including significant decrement in tangent los...

Polycarbosilane (PCS) has been widely used to fabricate silicon carbide (SiC) fibers via pyrolysis. In this paper, for improving the morphology of SiC fibers, tetraethyl orthosilicate (TEOS, m = 1 g, 3 g and 5 g, respectively) was added into the PCS precursor solution (containing 1.5 g PCS). The continuous fibers have been prepared by electrospinning, and then the SiC fibers were synthesized by calcination at 1300 ℃, 1400 ℃ and 1600 ℃ for 4 h respectively with a he...

We investigate the DC transport properties of 60V₂O₅–5P₂O₅–(35-x)B₂O₃–xDy₂O₃ (x = 0.4, 0.6, 0.8, 1.0 and 1.2 mol%) glasses as function of temperature which were prepared using the conventional melt-quenching method. These glasses are characterised by thermo gravimetric-differential thermal analysis (TG-DTA). Activation energy (E_DC) is obtained from Arrhenius plots of ...

0.67BiFeO₃–0.33BaTiO₃ multiferroic ceramics doped with x mol% MnO₂ (x = 2–10) were synthesized by solid-state reaction. The formation of a perovskite phase with rhombohedral symmetry was confirmed by X-ray diffraction (XRD). The average grain sizes were reduced from 0.80 μm to 0.50 μm as increasing the Mn-doped levels. Single crystalline nature of the grains was revealed by high-resolution transmission electron microscopy (HR...

In this paper, a simple and cheap method to prepare porous ZnO by using zinc nitrate, ethanol and triethanolamine (TEA) is reported. The as-prepared sample consisted of nano and micro pores. The sample was calcined at 300 ℃, 400 ℃ and 500 ℃ with different heating rates. At 500 ℃, the nano pores disappeared but the sample maintained its micro porosity. Field emission scanning electron microscopy (FE-SEM) pictures confirmed that the size and growth of ZnO nanoparticl...

MnCo₂O₄ octahedral structure with edge length about 500 nm was successfully synthesized by a simple hydrothermal route. With the use of NaOH, the chemical potential and the rate of ionic motion in the precursor solution were controlled, and the particle size was limited. The magnetization measurements revealed that the products exhibited ferrimagnetic characteristics with different saturation magnetization and coercivity at different measuring temperatures. In addition, ...

The objective of this study was to characterize the chemical and physical properties of bioactive ceramics prepared from an aqueous paste containing hydroxyapatite (HA) and beta tri-calcium phosphate (β-TCP). Prior to formulating the paste, HA and β-TCP were calcined at 800 ℃ and 975 ℃ (11 h), milled, and blended into 15%/85% HA/β-TCP volume-mixed paste. Fabricated cylindrical rods were subsequently sintered to 900 ℃, 1100 ℃ or 1250 ℃. T...

The electrical characteristics of hybrid super capacitor were evaluated by synthesizing LTO (Li₄Ti₅O₁₂) using TiO₂ having a hydrogen titanate nanowire form. Preparation of the hydrogen titanate nanowire was implemented by using TiO₂ having size of 60 nm and NaOH, and performing synthesis at 70 ℃ for 6 h with a sonochemical method. LTO compound was synthesized at 150 ℃ for 36 h and at 180 ℃ for 36 h respectively by usi...

Nanocrystalline calcium titanate (CT) ceramic has been synthesized by a combination of solid-state reaction and high-energy ball milling. This nano-ceramic is characterized by X-ray diffraction (XRD), dielectric study and impedance spectroscopy. The XRD pattern shows single phase ceramic of orthorhombic symmetry. The frequency-dependent dielectric study shows that the dielectric constant is maximized at low frequencies and decreases with an increase in frequency. Impedance spectroscopy analys...