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This study investigated the electrochemical corrosion properties of the solders for die-attach applications in 3.5% NaCl solution. Compared with Pb–5Sn and Zn–40Sn, Bi–11Ag exhibited higher corrosion potential and relatively low corrosion current density. The ductile Ag-rich phase which dispersed in the Bi matrix was able to accommodate the stress arising from the formation of a passive layer and contributed to the two-stage passivation. X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) results confirm that the corrosion products comprised BiOCl, Bi 2 O 3 and AgCl.

Copper ferrite nanopowders were successfully synthesized by a microwave-induced combustion process using copper nitrate, iron nitrate, and urea. The process only took a few minutes to obtain CuFe 2 O 4 nanopowders. The resultant powders were investigated by XRD, SEM, VSM, and surface area measurement. The results revealed that the CuFe 2 O 4 powders showed that the average particle size ranged from 300 to 600 nm. Also, it possessed a saturation magnetization of 21.16 emu/g, and an intrinsic coercive force of 600.84 Oe, whereas, upon annealing at 800 °C for 1 h. The CuFe 2 O 4 powders specific surface area was 5.60 m 2 /g. Moreover, these copper ferrite magnetic nanopowders also acted as a catalyst for the oxidation of 2,3,6-trimethylphenol to synthesize 2,3,5-trimethylhydrogenquinone and 2,3,5-trimethyl-1,4-benzoquinone for the first time. On the basis of experimental evidence, a rational reaction mechanism is proposed to explain the results satisfactorily.

Magnesium-substituted lithium ferrite of different composition (Li0.5Fe2.5−xMgxO4−δ) were prepared for x = 0.0–1.0 by conventional ceramic technique. The crystal structure characterization and morphology were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM). Initial permeability and quality factor were measured in the frequency range of 1 kHz to 100 MHz. The permeability decreased gradually from μ (f = 10 MHz) = 34.0 for Li0.5Fe2.5O4 to μ (f = 10 MHz) = 11.5 for Li0.5Fe1.5Mg1.0O4. Electrical conductivity measurements were carried in the range of 250–700 °C in air. The maximum electrical conductivity, σ700 °C = 0.1274 S/cm has been found to be for Li0.5Fe2.5O4 specimen. With increasing Mg-substituted content, the decreased in the electrical conductivity.

Bi2O3 was selected as liquid phase sintering aid to lower the sintering temperature of La(Mg0.5Ti0.5)O3 ceramics. The sintering temperature of La(Mg0.5Ti0.5)O3 ceramics is generally high, about 1600 °C. However, the sintering temperature was significantly lowered about 275 °C from 1600 °C to 1325 °C by incorporating in 15 mol% Bi2O3 and revealed the optimum microwave dielectric properties of dielectric constant (ɛr) value of 40.1, a quality factor (Q × f) value of 60,231 GHz, and the temperature coefficient (τf) value of 70.1 ppm/°C. During all addition ranges, the relative dielectric constants (ɛr) were different and ranged from 32.0 to 41.9, the quality factors (Q × f) were distributed in the range of 928–60,231 GHz, and the temperature coefficient (τf) varies from 0.3 ppm/°C to 70.3 ppm/°C. Noticeably, a nearly zero τf can be found for doping 5 mol% Bi2O3 sintering at 1325 °C. It implies that nearly zero τf can be achieved by appropriately adjusting the amount of Bi2O3 additions and sintering temperature for La(Mg0.5Ti0.5)O3 ceramics.

The microstructure, thermal expansion, microhardness, indentation fracture toughness, and ionic conductivity of neodymium-doped ceria (NDC) prepared by coprecipitation were investigated. The results revealed that the average particle size ( D BET ) ranged from 20.1 to 25.8 nm, crystallite dimension ( D XRD ) varied from 17.5 to 20.7 nm, and the specific surface area distribution was from 31.25 to 40.27 m 2 /g for neodymium-doped ceria stacking powders. Dependence of lattice parameter, a , versus dopant concentration, x , of Nd 3+ ion shows that these solid solutions obey Vegard's rule as a ( x ) = 5.4069 + 0.1642 x for Ce 1− x Nd x O 2−(1/2) x for x = 0.05–0.25. For neodymium-doped ceria ceramics sintered at 1500 °C for 5 h, the bulk density was over 95% of the theoretical density. The maximum ionic conductivity, σ 800°C = 4.615 × 10 −2 S/cm, with the minimum activation energy, E a = 0.794 eV was found for the Ce 0.75 Nd 0.25 O 1.875 ceramic. Trivalent, neodymium-doped ceria ceramics revealed high fracture toughness, the fracture toughness distribution was in the range of 6.236 ± 0.021 to 6.846 ± 0.017 MPa m 1/2 . The high indentation fracture toughness of neodymium-doped ceria was attributed to crack deflection. Moreover, the porosity may influence the mechanical properties such as microhardness and fracture toughness. It was observed that as the porosity reduced, the microhardness and fracture toughness increased.

SmBaCo2O5+δ (SBC) was studied as cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The crystal structure, thermal expansion behavior, and electrochemical performance with long-term operation of SBC were characterized. An orthorhombic layered perovskite structure was observed in SBC cathode by a GSAS program for refinement. The average thermal expansion coefficient (TEC) is 21.6 x 10-6K-1 in the temperature range of 100oC-800oC. For long-term testing, the polarization resistance of SBC cathode increases gradually from 25.77 Ω cm2 for 2 h to 38.77 Ω cm2 for 96 h at 600°C, and an increasing-rate for polarization resistance is around 13,8% h-1. Based on the electrochemical properties, SBC cathode with mixed ionic and electronic conductor (MIEC) behavior is a potential cathode for intermediate temperature solid oxide fuel cells based on a SDC electrolyte.

In the current research, we successfully prepared TiO2/Ni–Cu–Zn ferrite composite powder for magnetic photocatalyst. The core Ni–Cu–Zn ferrite powder was synthesized using the steel pickling liquor and the waste solution of electroplating as the starting materials. The shell TiO2 nanocrystal was prepared by sol-gel hydrolysis precipitation of titanium isopropoxide [Ti(OC3H7)4] on the Ni–Cu–Zn ferrite powder followed by heat treatment. From transmission electron microscopy (TEM) image, the thickness of the titania shell was found to be approximately 5 nm. The core of Ni–Cu–Zn ferrite is spherical or elliptical shape, and the particle size of the core is in the range of 70–110 nm. The magnetic Ni–Cu–Zn ferrite nanopowder is uniformly encapsulated in a titania layer forming core-shell structure of TiO2/Ni–Cu–Zn ferrite powder. The degradation efficiency for methylene blue (MB) increases with magnetic photocatalyst (TiO2/Ni–Cu–Zn ferrite powder) content. When the magnetic photocatalyst content is 0.40 g in 150 mL of MB, the photocatalytic activity reached the largest value. With a further increase in the content of magnetic photocatalyst, the degradation efficiency slightly decreased. This occurs because the ultraviolet (UV) illumination is covered by catalysts, which were suspended in the methylene blue solution and resulted in the inhibition in the photocatalytic reaction. The photocatalytic degradation result for the relationship between MB concentration and illumination revealed a pseudo first-order kinetic model of the degradation with the limiting rate constant of 1.717 mg/L·min and equilibrium adsorption constant 0.0627 L/mg. Furthermore, the Langmuir–Hinshelwood model can be used to describe the degradation reaction, which suggests that the rate-determining step is surface reaction rather than adsorption is in photocatalytic degradation.

Characteristics, such as lattice parameter, theoretical densities, thermal expansion, mechanical properties, microstructure, and ionic conductivities, of Ce0.8M0.2O2−δ (M = Y, Gd, Sm, Nd, La) ceramics prepared by coprecipitation were systematically investigated in this paper. The results revealed that the lattice parameter and density based on the oxygen vacancy radius generally agreed with experimental results. Ce0.8Sm0.2O2−δ ceramic sintered at 1500 °C for 5 h possessed the maximum ionic conductivity, σ800 °C = 6.54 × 10−2 S cm−1, with minimum activation energy, Ea = 0.7443 eV, among Ce0.8M0.2O2−δ (M = Y, Gd, Sm, Nd, La) ceramics. The thermal expansion coefficients of Ce0.8M0.2O2−δ (M = Y, Gd, Sm, Nd, La) were in the range of 15.176–15.571 ppm/°C, which indicates that the rare-earth oxide dopants have insignificant influence on the thermal expansion property. Trivalent, rare-earth oxide doped ceria ceramics revealed high fracture toughness, with the fracture toughness in the range of 6.393–7.003 MPa m1/2. According to SEM observation, the cracks are limited to one grain diameter; therefore, the high fracture toughness of rare-earth oxide doped ceria may be due to the toughness mechanism of crack deflection at the grain boundary. Based on the results of grain size and mechanical properties, one may conclude that there is no significant dependence of fracture toughness and microhardness for Ce0.8M0.2O2−δ ceramics on grain size. Correlation between the grain size of Ce0.8M0.2O2−δ ceramics and the dopant species can be explained on the basis of the concept of the rate of grain growth being proportional to the boundary mobility Mb. This leads to a conclusion that the diffusion coefficient of La in Ce0.8La0.2O2−δ>Nd in Ce0.8Nd0.2O2−δ>Sm in Ce0.8Sm0.2O2−δ>Gd inCe0.8Gd0.2O2−δ>Y in Ce0.8Y0.2O2−δ.

ZnO growth on sapphire by MOCVD using dimethylzinc and CO 2 as zinc and oxygen precursors was performed. A dense ZnO film with major (0 0 0 2) orientation can be prepared at 350 °C and above with high dimethylzinc flow rate. Result shows that the growth temperature suppresses the lateral growth of ZnO grains, promotes the coalescence of grains but reduces the crystal alignment. To further enhance the crystal alignment, a two-step temperature variation growth method is proposed. Using the two-step growth method, employing the initial growth at lower temperature followed by the growth at higher temperature, a densely packed ZnO film with larger grains and well-aligned (0 0 0 2) crystallographic orientation can be obtained. The effect of temperature on nucleation and growth rate, and its relation to the crystal alignment enhancement is also discussed.

In the current research, we proposed a new method called microwave-induced combustion synthesis to produce LiMn2O4 powders. The microwave-induced combustion synthesis entails the dissolution of metal nitrates, and urea in water, and then heating the resulting solution in a microwave oven. Spinel LiMn2O4 powders were successfully synthesized by microwave-induced combustion. The microwave-heated LiMn2O4 powders annealed at various temperatures in the range of 600–800 °C were determined. The resultant powders were characterized by X-ray diffractometer (XRD), and scanning electron microscopy (SEM). The annealed samples were used as cathode materials for lithium-ion battery, for which their discharge capacity and electrochemical characteristic properties in terms of cycle performance were also investigated. The LiMn2O4 cell provides a high initial capacity of 133 mAh/g and excellent reversibility. The excellent capacity and reversibility were attributed to LiMn2O4 powders with small and uniform particle size produced by microwave-induced combustion synthesis.

An aqueous tape casting of gadolinia-doped ceria (GDC) ceramics was developed using Poly(acrylic acid) PAA as dispersant, Poly(vinyl alcohol) PVA as binder, Poly(ethylene glycol) PEG as plasticizer, and deionized water as solvent. Surface properties of GDC powder with and without PAA dispersant were characterized by electrokinetic measurements. The zeta potential measurement revealed that the isoelectric point for GDC powders in the absence of dispersant corresponds to a pH value of 4.06. The experimental results showed that pH value greatly affects the rheology of the slurry. Homogeneous, smooth, and defect-free green tapes were successfully obtained by using an appropriate slurry formula. Moreover, the crystallization kinetics of GDC powders prepared by coprecipitation process also has been investigated in this study. The activation energy of crystallization was calculated by differential scanning calorimetry (DSC) at different heating rates. Analysis of non-isothermal DSC data presented values of 105.3 kJ/mol and 1.171 for the activation energy of crystallization presented and the Avrami exponent, respectively.

The influence of various sintering aids on the microwave dielectric properties and the structure of Nd(Mg 0.5 Ti 0.5 )O 3 ceramics were investigated systematically. B 2 O 3 , Bi 2 O 3 , and V 2 O 5 were selected as liquid-phase sintering aids to lower the sintering temperature. The sintered Nd(Mg 0.5 Ti 0.5 )O 3 ceramics are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and microwave dielectric properties. The sintering temperature of Nd(Mg 0.5 Ti 0.5 )O 3 microwave dielectric ceramics is generally high, about 1500 °C. However, the sintering temperature was significantly lowered about 175 °C from 1500 °C to 1325 °C by incorporating in 10 mol% B 2 O 3 and revealed the optimum microwave dielectric properties of dielectric constant ( ɛ r ) value of 26.2, a quality factor ( Q × f ) value of 61,307 (at 9.63 GHz), and τ f value of −45.5 ppm/°C. NdVO 4 secondary phase was observed at 10 mol% V 2 O 5 addition in the sintering temperature range of 1300–1325 °C, which led the degradation in microwave dielectric properties. The microwave dielectric properties as well as grain sizes, grain morphology, and bulk density were greatly dependent on sintering temperature and various sintering aids. In this study, it is found that Nd(Mg 0.5 Ti 0.5 )O 3 incorporated with 10 mol% B 2 O 3 with lower sintering temperature and excellent dielectric microwave properties may be suggested for application in microwave communication devices. The use of liquid-phase sintering, the liquid formed during firing normally remains as a grain boundary phase on cooling. This grain boundary phase can cause a deterioration of the microwave properties. Therefore, the selection of a suitable sintering aid is extremely important.

A non-isothermal study of the crystallization kinetic of coprecipitation of Bi 1.25 Y 1.75 Fe 5 O 12 was carried out by differential scanning calorimetry (DSC). The Avrami exponent n suggesting the dimensionality of crystal growth was determined using the Ozawa equation. From non-isothermal DSC data presented values in range of 775–1023 kJ/mol and 3.28–2.10 for the activation energy of crystallization and the Avrami exponent, respectively. These Avrami exponent values were consistent with surface and internal crystallizations growth simultaneously.

A structure characterization of chromium-substituted lithium ferrite specimens was carried out by the X-ray diffraction technique and found that the lattice parameter decreases with increasing of Cr-substitution content and the microstructure was determined by scanning electron microscopy (SEM), which revealed that the average grain size of chromium-substituted lithium ferrite decreases gradually with increasing Cr-substitution content. The magnetic moments calculated from Neel's molecular field model are in agreement in the experiment result, which indicates that the saturation magnetization decreases monotonically with increasing Cr-substitution content. The values of saturation magnetization (Ms) for Li 0.5 Fe 1.5− x Cr x O 4 specimens decrease from 38.9 emu/g for x = 0.0 to 9.9 emu/g for x = 1.0. The microwave properties (complex permittivity and permeability) were measured in the 8–13 GHz frequency range by the cavity perturbation. The systematic variations of the real and imaginary parts of both permittivity and permeability with frequency and composition have been analyzed. The real and imaginary parts of both permittivity and permeability values decreased gradually with increasing frequency. The real part of permittivity ɛ ′ values are found to vary in the range of 15.44–12.37, and the real part of permeability μ ′ values are found to vary in the range of 3.95–1.27.

The microstructure, lattice parameters, electrical conductivity, thermal expansion, and mechanical properties of (La0.8Ca0.2)(Cr0.9–xCo0.1Nix)O3–δ (x = 0.03, 0.06, 0.09, 0.12) were systematically investigated in this work. Nickel doping of (La0.8Ca0.2)(Cr0.9Co0.1)O3–δ is an effective way of increasing the thermal expansion coefficient (TEC) and stabilizing the high-temperature phase transformation from rhombohedral to tetragonal. As the nickel-doped content increases, the TEC increases parabolically by TEC (x) (ppm/°C) = 10.575 + 63.3x−240x2 (x = 0.03−0.12). The electrical conductivity of (La0.8Ca0.2)(Cr0.9–xCo0.1Nix)O3–δ specimens increases systematically with increasing nickel substitution in the range of 0.03 ≤ x ≤ 0.09 and reaches a maximum for the composition of (La0.8Ca0.2)(Cr0.81Co0.1Ni0.09)O3–δ (σ850 °C ∼60.36 S/cm). There is a slight increase in the fracture toughness with increasing nickel doping content, and the fracture toughness is strongly affected by the grain size. It seems that there is an increase in the fracture toughness with decreasing grain size. However, the microhardness does not significantly depend on the grain size in this study. The (La0.8Ca0.2)(Cr0.81Co0.1Ni0.09)O3–δ specimen shows high electrical conductivity, a moderate thermal expansion coefficient, and nearly linear thermal expansion behavior from room temperature to 800 °C. It will be suitable for interconnect materials for intermediate temperature solid oxide fuel cells (IT-SOFCs).

Cr-substituted lithium ferrite of different composition (Li 0.5 Fe 2.5− x Cr x O 4 ) were prepared for x = 0.0–1.0 by conventional ceramic technique. A structure characterization of all the samples was carried out by the X-ray diffraction technique and found that the lattice parameter decreases with increasing of Cr-substituted concentration. Magnetic properties such as permeability and quality factor were measured in the frequency range of 1 kHz to 100 MHz. The permeability and quality factor of Cr-substituted lithium ferrite were strongly affected by Cr-substituted concentration. The permeability decreased gradually from μ ( f = 10 MHz) = 34.9 for Li 0.5 Fe 2.5 O 4 to μ ( f = 10 MHz) = 4.0 for Li 0.5 Fe 1.5 Cr 1.0 O 4 . The electrical conductivity and activation energy were measured by the DC two probes technique. The temperature dependence of DC conductivity shows the semiconductor nature. A change of slope in the Arrhenius plot (log σT vs. 10 3 / T ) may be due to the ferri to paramagnetic transition. The conductivity variation shows two different regions with a large variation in the activation energy. The activation energies in the ferromagnetic region are greater than those in the paramagnetic region.

The formation enthalpy and magnetic properties of bismuth-doped yttrium iron garnet powders were investigated. The formation enthalpy and the crystallization temperature both decreased with increasing bismuth substitution for Bi x Y 3− x Fe 5 O 12 (0.25 ≦ x ≦ 1.25) powders prepared by the coprecipitation process. Bi substitution for Y can significantly reduce crystallization temperature for bismuth-doped yttrium iron garnet powders, and the magnetic properties (saturation magnetization, remanence, and coercive force) are independent of Bi substitution amounts. The average particle size has been determined by the specific surface area. As Bi substitution for Y increased, the average particle size also increased, while the specific surface area decreased.

Olivine structured LiFePO 4 (lithium iron phosphate) and Ti 4+ -doped LiFe 1− x Ti x PO 4 (0.01 ≤ x ≤ 0.09) powders were synthesized via a solution route followed by heat-treatment at 700 °C for 8 h under N 2 flowing atmosphere. The compositions, crystalline structure, morphology, carbon content, and specific surface area of the prepared powders were investigated with ICP-OES, XRD, TEM, SEM, EA, and BET. Capacity retention study was used to investigate the effects of Ti 4+ partial substitution on the intercalation/de-intercalation of Li + ions in the olivine structured cathode materials. Among the prepared powders, LiFe 0.97 Ti 0.03 PO 4 manifests the most promising cycling performance as it was cycled with C/10, C/5, C/2, 1C, 2C, and 3C rate. It showed initial discharge capacity of 135 mAh g −1 at 30 °C with C/10 rate. From the results of GSAS refinement for the prepared samples, the doped-Ti 4+ ions did not occupy the Fe 2+ sites as expected. However, the occupancy of the doped Ti 4+ ions are still not clear, and theoretical calculations are needed for further studies. From the variation of lattice parameters calculated by the least square method without refinement, it suggested that Ti 4+ -doped LiFePO 4 samples formed solid solutions at low doping levels while TiO 2 was also observed with TEM in samples prepared with doping level higher than 5 mol%.

The structure, magnetic, and thermal expansion properties of chromium-substituted lithium ferrite have been investigated. The lattice constant (A) decreases linearly as a ( x ) = 8.32366 − 0.04338 x for Li 0.5 Fe 2.5− x Cr x O 4 ( x = 0.0–1.0). When increasing Cr content, the initial permeability decreased gradually. The average thermal expansion coefficient of Li 0.5 Fe 2.5− x Cr x O 4 ( x = 0.0–1.0) varied from 15.34 to 17.77 ppm/°C, with increasing Cr content, the average thermal expansion coefficient decreased. The average thermal expansion coefficient (ppm/°C) in the range of 25–850 °C give the polynomial correlation as follows, TEC ( x ) = 1 7.775 − 0.216 x − 0.723 x 2 − 1.493 x 3 for Li 0.5 Fe 2.5− x Cr x O 4 ( x = 0.0–1.0).

An aqueous tape casting of Ce 0.8 Sm 0.2 O 1.9 (SDC) ceramics was developed using poly(acrylic acid) (PAA) as dispersant, poly(vinyl alcohol) (PVA) as binder, poly(ethylene glycol) (PEG) as plasticizer, and deionized water as solvent. Surface properties of SDC powder with and without PAA dispersant were characterized by electrokinetic measurements. The rheology of the SDC slurries was evaluated with a rotary viscometer. The zeta potential measurement showed that the isoelectric point (IEP) for SDC powders in the absence of dispersant corresponds to a pH value of 3.66. The experimental results showed that the pH value greatly affects the rheology of the slurry. The optimum content to get a stable dispersed slurry is 2 wt% PAA in pH value range of 9–10. In presence of 2 wt% PAA dispersant, 55 wt% SDC powders exhibited shear thinning behavior, indicating that SDC slurry was homogenous and well stabilized. Homogeneous, smooth, and defect-free green tapes were successfully obtained by an appropriate slurry formula.

We developed a new method, i.e. microwave-induced combustion synthesis to produce highly sinterable Y 2 O 3 -doped CeO 2 nanopowders. The process took only 15 min to yield Y 2 O 3 -doped CeO 2 powders. We also investigated the conductivity of Y 2 O 3 -doped CeO 2 ceramics. It was found Y 2 O 3 concentration to have a large effect on the morphology, activation energy, ionic conductivity, and mechanical properties of Y 2 O 3 -doped CeO 2 ceramics. The results revealed that the bulk densities of Y 2 O 3 -doped CeO 2 ceramics sintered at 1420 °C for 5 h were all higher than 92% of the theoretical densities, and the maximum ionic conductivity, σ 800 °C = 0.023 S/cm at 800 °C, the minimum activation energy, E a = 0.954 eV determined in the temperature of 300–800 °C and the maximum fracture toughness, K IC = 1.825 ± 0.188 MPa m 1/2 were found for 9 mol.% Y 2 O 3 -doped CeO 2 specimen. The grain size of CeO 2 decreases with increasing Y 2 O 3 concentration. The fracture toughness was found to increase at increased Y 2 O 3 concentration, because of the decrease of CeO 2 grain size.

The non-isothermal crystallization kinetics of Bi0.75Y2.25Fe5O12 powder prepared by coprecipitation has been investigated. The activation energy of crystallization was calculated by differential scanning calorimetry (DSC) at different heating rates. Analysis of non-isothermal DSC data presented values of 650 kJ/mol and 2.48 for the activation energy of crystallization and the Avrami exponent, respectively. This Avrami exponent value was consistent with surface and internal crystallizations occurring simultaneouly. The complex permittivity and permeability of Bi0.75Y2.25Fe5O12 were measured at X-band (8–12 GHz) by cavity perturbation technique. For dielectric properties, the real part of permittivity, ɛ′, was obtained in the range of 13.18–15.28. For magnetic properties, the real part of permeability, μ′, was obtained in the range of 12.21–20.98.

An aqueous tape casting of Ce 0.8 La 0.2 O 1.9 (LDC) ceramics was developed using PAA as dispersant, PVA as binder, PEG as plasticizer, and deionized water as solvent. Surface properties of LDC powder with and without PAA dispersant were characterized by electrokinetic measurements. The rheology of the LDC slurries was evaluated with a rotary viscometer. The zeta potential measurement showed that the isoelectric point for LDC powders in the absence of dispersant corresponds to a pH value of 4.02. The experimental results showed the pH value greatly affects the rheology of the slurry. The optimum content to get a stable dispersed slurry is 1.5 wt% PAA at pH value of 9–10. In presence of 1.5 wt% PAA dispersant, 5 wt% PVA binder, 5 wt% PEG plasticizer, and 55 wt% LDC powders exhibited shear thinning behavior, indicating that LDC slurry was homogenous and well stabilized. With an appropriate formulation homogeneous, smooth, and defect-free green tapes were successfully obtained. Moreover, the crystallization kinetics of LDC powders prepared by coprecipitation process also has been investigated in this study. The activation energy of crystallization was calculated on the basis of differential scanning calorimetry (DSC) at different heating rates. From non-isothermal DSC data presented values in the range of 343.3–379.1 kJ/mol and 2.282–2.030 for the activation energy of crystallization and the Avrami exponent, respectively, at specific temperatures ranging from 280 to 285 °C.

Copper ferrite nano-particles with Fe/Cu ratios varying from 2 to 12 were successfully synthesized by combustion process using copper nitrate, iron nitrate and urea. The resultant powders were investigated by scanning electron microscopy (SEM), vibrating sample magnetometer (VSM). The results revealed that the copper ferrite powders are uniform in the range of 250-300 nm. The copper ferrite with Fe/Cu ratio of 2 possessed a saturation magnetization of 5.47 emu/g, and an intrinsic coercive force of 241.98 Oe, with Fe/Cu ratio of 12 possessed a saturation magnetization of 22.06 emu/g and an intrinsic coercive force of 247.94 Oe. Moreover, these copper ferrite magnetic nano-particles also acted as catalyst for the oxidation of 2,3,6-trimethylphenol to synthesize 2,3,5-trimethylhydrogenquinone and 2,3,5-trimethyl-1,4-benzoquinone for the first time. The conversion of 2,3,6-trimethylphenol in the kinetic behavior of oxidation was investigated in detail. The reaction shows dramatically enhanced by the addition of copper-ferrite nano-particles to the solution.

Ce0.8(Gd0.2−xSmx)O1.90 nanopowders were successfully synthesized by a microwave-induced combustion process. The whole process takes only 30 min. The phase identification and morphology of resultant powders were investigated by XRD and SEM. Moreover, the correlation of ionic conductivity and thermal expansion coefficient for Ce0.8(Gd0.2−xSmx)O1.90 ceramics from microwave-induced combustion process also is discussed in this paper. The results revealed that the bulk densities of Ce0.8(Gd0.2−xSmx)O1.90 ceramics sintered at 1450 °C for 3 h were all greater than 95% of that in theoretical densities. The maximum electrical conductivity, σ850°C = 0.051 S/cm, minimum activation energy, Ea = 0.77 eV and minimum thermal expansion coefficient, TEC = 18.733 ppm/°C was found at Ce0.80Gd0.20O1.90 ceramic.

The non-isothermal crystallization kinetics of Bi0.25Y2.75Fe5O12 powder prepared by the coprecipitation process has been investigated. The activation energy of crystallization was calculated by differential scanning calorimetry (DSC) at different heating rates. From non-isothermal DSC data presented values in the range of 712–772 kJ/mol and 2.90–3.46 for the activation energy of crystallization and the Avrami exponent, respectively at specific temperature ranging form 750.0 to 757.5 °C. This value for the Avrami exponent indicates that the controlling mechanism of crystallization is three-dimensional interfacial growth.

An aqueous tape casting of Ce0.8Y0.2O1.9 (YDC) ceramics was developed using poly(acrylic acid) (PAA) as a dispersant, poly(vinyl alcohol) (PVA) as a binder, poly(ethylene glycol) (PEG) as a plasticizer, and deionized water as a solvent. The surface properties of YDC powder with and without PAA dispersant were characterized by zeta potential. The rheological of the YDC slurries was evaluated with a rotary viscometer. The zeta potential measurement showed that the isoelectric point for YDC powders in the absence of dispersant had a pH value of 3.35. The experiment results showed that the pH value greatly affects the rheology of the slurry. In the presence of 2 wt % PAA dispersant, 55 wt % YDC powders exhibited shear thinning behavior, indicating that YDC slurry was homogenous and well stabilized. With an appropriate formulate, homogeneous, smooth, and defect-free green tapes were successfully obtained. Moreover, the crystallization kinetics of YDC powders prepared by the coprecipitation process has also been investigated in this study. The activation energy of crystallization was calculated on the basis of differential scanning calorimetry (DSC) at different heating rates. The activation energy of crystallization presented a value of 192.8 kJ/mol.

A novel ceramic synthesis technique, combustion process was investigated for the production of phosphor powders. In this study, we have developed a new method to product phosphor powders, and applied this process into two materials fabrication. Y3Al5O12:Ce and Y2O3:Eu phosphor powders were successfully synthesized by combustion process. The process takes only 15 min to obtain Y3Al5O12:Ce and Y2O3:Eu phosphor powders. The resultant phosphor powders were investigated by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), photoluminescence excitation and emission spectra (PL), scanning electron microscope (SEM), and transmission electron microscopy (TEM). The results revealed that the formation temperature of phase is significant low, compared to solid-state reaction route of constituent oxides.

The nonisothermal crystallization kinetic of BixY3−xFe5O12 (0.25≤x≤1.00) powders prepared by coprecipitation process has been investigated. The activation energy of crystallization was calculated by differential scanning calorimetry at different heating rates. The activation energies of crystallization of BixY3−xFe5O12 system are 492, 447, 377, and 353 kJ/mol and the Avrami constant n are 3.49, 2.25, 2.48, and 2.33 for x=0.25, 0.50, 0.75, and 1.00, respectively. The Avrami exponent values (1 3) for the Avrami exponent was consistent with bulk crystallization domination in BixY3−xFe5O12 system. The results reveal that increasing the substitution amount of bismuth for yttrium would significantly decrease activation energy in BixY3−xFe5O12 system.

The structure, thermal expansion and electrical conductivity of Ce 0.8 (Gd 1− x Bi x ) 0.2 O 1.9 ( x = 0.1–0.5), prepared by coprecipitation were investigated. Ce 0.8 (Gd 1− x Bi x ) 0.2 O 1.9 ceramics was sintered in the range of 1350–1450 °C for 6 h; the bulk density of Ce 0.8 (Gd 1− x Bi x ) 0.2 O 1.9 ceramics was over 95% of the theoretical density; the maximum electrical conductivity, σ 800 °C = 0.078 S/cm with minimum activation energy, E a = 0.638 eV was found for the Ce 0.8 (Gd 0.5 Bi 0.5 ) 0.2 O 1.90 ceramic. The gadolinium-doped ceria ceramics preparation by coprecipitation can reduce the sintering temperature by addition of bismuth. The thermal expansion coefficient of Ce 0.8 (Gd 1− x Bi x ) 0.2 O 1.9 covers the range of 20.132–20.478 ppm/°C. The ceramic has a fracture toughness in the range of 1.28–2.60 MPa m 1/2 for dense Ce 0.8 (Gd 1− x Bi x ) 0.2 O 1.9 ceramics. The value of fracture toughness increased with Bi content. It indicated that the mechanical properties of gadolinium-doped ceria ceramics could be improved by addition of bismuth.

The microstructure, thermal expansion, mechanical property, and ionic conductivity of samaria-doped ceria (SDC) prepared by coprecipitation were investigated in this paper. The results revealed that the average particle size ranged from 10.9±0.4 to 13.5±0.5 nm, crystallite dimension varied from 8.6±0.3 to 10.7±0.4 nm, and the specific surface area distribution ranged from 62.6±1.8 to 76.7±2.2 m2/g for SDC powders prepared by coprecipitation. The dependence of lattice parameter, a, versus dopant concentration, x, of Sm3+ ion shows that these solid solutions obey Vegard's rule as a (x)=5.4089+0.10743x for Ce1−xSmxO2−1/2x. For SDC ceramics sintered at 1500°C for 5 h, the bulk density was over 95% of the theoretical density; the maximum ionic conductivity, σ800°C=(22.3±1.14) × 10−3 S/cm with minimum activation energy, Ea=0.89±0.02 eV, was found in the Ce0.80Sm0.20O1.90 ceramic. A dense Ce0.8Sm0.2O1.9 ceramic with a grain size distribution of 0.5–4 μm can be obtained by controlling the soaking time at 1500°C. When the soaking time was increased, the microhardness of Ce0.8Sm0.2O1.9 ceramic increased, the toughness slightly decreased, which was related to grain growth with the soaking time.

The crystallization kinetics of Bi0.5Y2.5Fe5O12 powders prepared by the coprecipitation process have been investigated. The activation energy of crystallization was calculated on the basis of differential scanning calorimetry at different heating rates. Analysis of nonisothermal DSC data yielded a value of 823.8 kJ/mol and 2.25 for the activation energy of crystallization and the Avrami exponent, respectively. This value for the Avrami exponent was consistent with surface and internal crystallization occurring simultaneously. The complex permittivity and permeability of Bi0.5Y2.5Fe5O12 was measured at the X-band (8–12 GHz) using the cavity perturbation technique. For dielectric properties, the real part of permittivity, ɛ′, was obtained in the range of 13.57–16.37. For magnetic properties, the real part of permeability, μ′, was obtained in the range of 21.61–16.90.

The non-isothermal crystallization kinetics of Bi1.0Y2.0Fe5O12 powder prepared by coprecipitation has been investigated. The activation energy of crystallization was calculated by differential scanning calorimetry (DSC) at different heating rates. Analysis of non-isothermal DSC data presented values of 634 kJ/mol and 2.33 for the activation energy of crystallization and the Avrami exponent, respectively. This Avrami exponent value was consistent with surface and internal crystallizations occurring simultaneously. The complex permittivity and permeability of Bi1.0Y2.0Fe5O12 were measured at X-band (8–12 GHz) by cavity perturbation. For dielectric properties, the real part of permittivity, e', was obtained in the range of 13.44–15.26. For magnetic properties, the real part of permeability, µ', was obtained in the range of 21.39–12.17.

In this study, we propose a process to prepare Mn–Zn ferrite powder, using oxides of manganese and zinc extracted from used dry batteries, and ferrous chloride solution from waste steel pickling liquor. The hydrothermal process was used to convert the starting raw materials into Mn–Zn ferrite powder. This powder revealed the formation of cubic ferrite with a saturation magnetization (Ms) of 58.8 emu/g and an intrinsic coercive force (Hc) of 3.8 Oe. The average lattice thermal expansion coefficient αa (200°–500°C) of this Mn–Zn ferrite powder was 14.14 × 10−6 K−1. The toroidal specimen sintered at 1300°C in a controlled oxygen atmosphere presented a flat profile of initial permeability (μi) of 2150–2200, in the frequency range 0.1–20 kHz, which allows its use in magnetic applications. This useful technology, combined with environment and materials engineering, can promote the recycling of dry batteries and contribute to the preservation of the earth. Moreover, this technology can also decrease the cost of disposal of the used dried batteries and waste steel pickling liquor.

Yttrium iron garnet (YIG) nano-powders were successfully synthesized by microwave-induced combustion process. The as-prepared YIG powders were annealed at different temperature and investigated by XRD, SEM, and VSM. The as-received YIG powder shows the formation of garnet structure with saturation magnetization (M s) of 12 emu/g, whereas upon annealing at 825 °C for 2 h, the saturation magnetization increases to 27 emu/g. The as-received yttrium iron garnet powders annealed at several temperatures revealed that the particle size ranged from 65 to 90 nm. Moreover, the linewidth of magnetic resonance peak (ΔH), complex permeability, and loss tangent of sintered YIG ceramic are also examined in this study.

Europium-doped yttrium phosphors were successfully synthesized by combustion process using yttrium nitrate hexahydrate [Y(NO3)3·6H2O], europium nitrate [Eu(NO3)3·6H2O], and carbohydrazide [CO(N2H3)2]. The process takes only a few minutes to obtain Y2O3:Eu phosphors. The resultant powders annealed at different temperature and were investigated by X-ray diffractometer (XRD), differential thermal analyzer/thermogravimeter (DTA/TG), Fourier transform infrared spectroscopy (FTIR), photoluminescence excitation and emission spectra (PL), and transmission electron microscopy (TEM). The results showed that the formation temperature of Y2O3 phase is significant low, compared to solid-state reaction route of constituent oxides. For luminescence property, the emission intensity of Y2O3:Eu phosphors synthesized by combustion process increases steadily with increasing europium amount from 1 mol% to 5 mol%.

Spinel LiMn2−yMyO4 (M = Cr and Co, where y = 0.0, 0.1, and 0.2) powders with narrow and uniformly sized particles were successfully synthesized by microwave-induced combustion, using lithium nitrate, manganese nitrate, chromium nitrate, cobalt nitrate, and urea as the starting materials. The LiMn2−yMyO4 powders synthesized by microwave-induced combustion were investigated by thermogravimeter analyzer (TGA), X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The Cr and Co-substituted spinel samples were used as cathode materials for lithium-ion battery, whose discharge capacity and electrochemical characteristic properties in terms of cycle performance were also investigated. The results revealed that the Li/LiMn2−yMyO4 (M = Cr, Co) cells can be ranked in terms of initial capacity as follows: LiMn2O4 > LiMn1.9Cr0.1O4 > LiMn1.9Co0.1O4 > LiMn1.8Cr0.2O4 > LiMn1.8Co0.2O4. The Li/LiMn2−yMyO4 (M = Cr, Co) cells showed lower fading rate than Li/LiMn2O4 cell during 30 cycles, while Cr-substituted spinel exhibited the lower fading rate than Co-substituted spinel. On the other hand, the fading rate of Li/LiMn2−yMyO4 cells can be ranked as follows: LiMn2O4 > LiMn1.9Co0.1O4 > LiMn1.8Co0.2O4 > LiMn1.9Cr0.1O4 > LiMn1.8Cr0.2O4.

Ce1−xGdxO2−1/2x nanopowder were successfully synthesized by microwave-induced combustion process. For the preparation, cerium nitrate, gadolinium nitrate hexahydrate, and urea were used for the microwave-induced combustion process. The process took only 30 min to obtain Ce1−xGdxO2−1/2x powders. The exo-endo temperature, phase identification, and morphology of resultant powders were investigated by TG/DTA, XRD, and SEM. The as-received Ce1−xGdxO2−1/2x powders showed that the average particle size ranged from 18 to 50 nm, crystallite dimension varied from 11 to 20 nm, and the specific surface area was distribution from 16 to 46 m2/g. As for Ce1−xGdxO2−1/2x ceramics sintered at 1450 °C for 3 h, the bulk density of Ce1−xGdxO2−1/2x ceramics were over 91% of the theoretical density, the maximum electrical conductivity, σ700 °C = 0.017 S/cm with minimum activation energy, Ea = 0.869 eV was found at Ce0.80Gd0.20O1.90 ceramic.

Ce 1− x Sm x O 2−1/2 x nanopowders were successfully synthesized by microwave-induced combustion process. For the preparation, cerium(III) nitrate hexahydrate, samarium(III) nitrate hexahydrate, and urea were used for the microwave-induced combustion process. The process took only a few minutes to obtain Ce 1− x Sm x O 2−1/2 x powders. Ce 1− x Sm x O 2−1/2 x ceramics prepared by microwave-induced process sintered at 1400 °C for 3 h, the bulk density of Ce 1− x Sm x O 2−1/2 x ceramics were over 95% of the theoretical density. The results revealed that Ce 0.84 Sm 0.16 O 1.92 possessed the maximum electrical conductivity was 0.0287 S cm −1 at 850 °C and the minimum activity energy, E a was 0.9565 eV determined from 500 to 850 °C.

Spinel LiMn1.925M0.075O4 (M = Cr, Co) powders with small and uniform particle size were successfully synthesized by microwave-induced combustion. The LiMn1.925M0.075O4 (M = Cr, Co) samples were used as cathode materials for lithium-ion battery, which their discharge capacity and electrochemical characteristic properties were investigated in this study. The results revealed that The Li/LiMn1.925M0.075O4 (M = Cr, Co) cells showed lower capacity loss than Li/LiMn2O4 cell after 30 cycles. Moreover, Cr-substituted spinel exhibited a lower capacity loss than Co-substituted spinel. The initial capacity of LiMn2O4 and LiMn1.925M0.075O4 cells can be ranked as follows: LiMn2O4 > LiMn1.925Cr0.075O4 > LiMn1.925Co0.075O4.

Spinel LiMn2 − xCoxO4 (0.00 ≦ x ≦ 0.20) powders with small and uniform particle size were successfully synthesized by microwave-induced combustion using lithium nitrate, manganese nitrate, cobalt nitrate, and urea as the starting materials. The LiMn2 − xCoxO4 powders synthesized by microwave-induced combustion were investigated by X-ray diffractometer (XRD), thermogravimeter analyzer (TG), and scanning electron microscopy (SEM). The LiMn2 − xCoxO4 samples were used as cathode materials in lithium-ion batteries, whose discharge capacity and electrochemical characteristics such as the cycling performance were also investigated. The results revealed that the LiMn2 − xCoxO4 cell synthesized by microwave-induced combustion provided a high initial capacity and excellent reversibility compared to the material prepared by solid-state reaction method.

Li 0.5 Fe 2.5− x M x O 4 (M = Al, Cr, Mn) powders with small and uniformly sized particles were successfully synthesized by microwave-induced combustion, using lithium nitrate, ferric nitrate, aluminum nitrate, chromium nitrate, manganese nitrate, and carbohydrazide as the starting materials. The process takes only a few minutes to obtain as-received Al, Cr, and Mn-substituted lithium ferrite powders. The resultant powders annealed at 650 °C for 2 h and were investigated by thermogravimeter/differential thermal analyzer (TG/DTA), X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermomagnetic analysis (TMA). The results revealed that saturation magnetization and Curie temperature of Li 0.5 Fe 2.5− x M x O 4 were strongly affected by different metal ions substitution.

Li0.5Fe2.5−xAlxO4 (0 ≦ x ≦ 1.0) powders with small and uniformly sized particles were successfully synthesized by microwave-induced combustion, using lithium nitrate, iron nitrate, aluminium nitrate, and carbohydrazide as the starting materials. The process takes only a few minutes to obtain as-received Al-substituted lithium ferrite powders. The resultant powders annealed at 650 °C for 2 h and were investigated by thermogravimeter/differential thermal analyzer (TG/DTA), X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermomagnetic analysis (TMA). The results revealed that the lattice constant, powder density, and crystallite size decrease linearly with the increasing of Al content in Li0.5Fe2.5−xAlxO4 samples. Moreover, the magnetic properties of Al-substituted lithium ferrite also strongly affected by Al content. The saturation magnetization, remanent magnetization, Curie temperature, and coercive force decrease significantly with the increasing of Al content.

A novel procedure for synthesizing submicron crystalline single-phase ceramic powder was investigated. Ultrafine CeO 2 powder was successfully prepared by combustion of mixture of cerium nitrate (oxidizer) and urea (fuel) in microwave oven for 15 min. The ultrafine powder was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), differential thermal analysis and thermogravimetric analysis (DTA/TG); surface area measurement was also made. The results indicated that the CeO 2 powders synthesized by microwave-induced combustion had particle sizes ranging from 20 to 50 nm, and specific surface areas of approximately 43 m 2 /g. In comparison, CeO 2 powder prepared by precipitation revealed particles of sizes distributed from 30 to 50 nm, with a specific surface area of about 48 m 2 /g.

Li0.5Fe2.5−xMnxO4 (0≦x≦1.0) powders with small and uniformly sized particles were successfully synthesized by microwave-induced combustion, using lithium nitrate, ferric nitrate, manganese nitrate and carbohydrazide as the starting materials. The process takes only a few minutes to obtain as-received Mn-substituted lithium ferrite powders. The resultant powders annealed at 650 °C for 2 h and were investigated by thermogravimeter/differential thermal analyzer (TG/DTA), X-ray diffractometer (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermomagnetic analysis (TMA). The results revealed that the Mn content were strongly influenced the magnetic properties and Curie temperature of Mn-substituted lithium ferrite powder. As for sintered Li0.5Fe2.5−xMnxO4 specimens, substituting an appropriate amount of Mn for Fe in the Li0.5Fe2.5−xMnxO4 specimens markedly improved the complex permeability and loss tangent.