scholarly journals Rapid Microwave Synthesis and Structural Phase Diagram of LnxY1−xMnO3

2014 ◽  
Vol 69 (7) ◽  
pp. 761-766 ◽  
Author(s):  
Fred P. Marlton ◽  
Darren J. Goossens ◽  
Reyner White ◽  
Wayne D. Hutchison
Keyword(s):  
Phase Diagram ◽  
Microwave Synthesis ◽  
Single Phase ◽  
Microwave Sintering ◽  
Structural Phase ◽  
Conventional Sintering ◽  
The Stability ◽  
Related Compounds ◽  
Sintering Method

YMnO3 is one of the primary examples of a multiferroic ceramic. We present a novel solid-state microwave sintering method for making high-purity ceramic samples of YMnO3 and related compounds in a few hours. This leads to determination of the structural phase diagram for the formation of single-phase, hexagonal samples when doping lanthanides into YMnO3. It is found that the solidstate microwave synthesis allows manufacture of high-quality samples in hours rather than days. The resulting phase diagram accords well with results from the literature, and from calculations based on the Goldschmidt tolerance factor for the stability of perovskite structures, suggesting that the transformation from hexagonal to perovskite with doping is driven essentially by ion sizes. Some results concerning the microwave synthesis of BaLnInO4 compounds, where Ln is a lanthanide, are noted. Microwave sintering of BaNdInO4 yields single-phase samples where conventional sintering does not.

STRUCTURAL, ELECTRICAL AND MAGNETIC CHARACTERIZATION OF Ni–Cu–Zn SPINEL FERRITES

2011 ◽  
Vol 25 (03) ◽  
pp. 211-222 ◽  
Author(s):  
M. PENCHAL REDDY ◽  
M. VENKATA RAMANA ◽  
N. RAMA MANOHAR REDDY ◽  
K. V. SIVA KUMAR ◽  
R. RAMA KRISHNA REDDY ◽  
...  
Keyword(s):  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Initial Permeability ◽  
Electromagnetic Devices ◽  
Zn Ferrite ◽  
Conventional Sintering ◽  
Tan Δ ◽  
Sintering Method

Ni – Cu – Zn ferrite materials have been extensively used in multilayer chip inductors because of their remarkable properties at higher frequencies. In the present work, single phase Ni 0.35 Cu 0.05 Zn 0.60 Fe 1.98 O 4-δ ferrite, has been prepared by microwave sintered (MS) method. In comparison with the conventional sintering method (CS), the sintering temperature and time for this MS method were significantly reduced to 30 min and 950°C from 5 h and 1250°C for the CS process. The frequency dependence of the dielectric properties such as dielectric constant (ε'), dielectric loss ( tan δ) were studied. The temperature dependence of magnetic initial permeability (μi) was studied. The saturation magnetization was also studied as a function of magnetic field. These microwave sintered ferrites results were compared with the properties of ferrites prepared by conventional sintering method in normal heating. Microwave sintering improves structural as well as electromagnetic parameters measured and thus makes the ferrite more suitable in microwave applications and electromagnetic devices.

Formation of Tricalcium Silicate Prepared by Electric and Microwave Sintering

2010 ◽  
Vol 148-149 ◽  
pp. 1119-1123
Author(s):  
Kai Ke ◽  
Bao Guo Ma ◽  
Xiao Liang Wang ◽  
Xiang Guo Li
Keyword(s):  
Heating Temperature ◽  
Microwave Sintering ◽  
Electric Heating ◽  
Tricalcium Silicate ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conventional Sintering ◽  
Sintering Method

A microwave sintering method was used to prepare C3S from Ca(OH)2, SiO2 and MexOy. f-CaO assay, X-ray diffraction and SEM were used to characterize the sintered samples.The results indicated that ion oxides played a very important role in C3S formation in conventional sintering, the use of MexOy as an additive was so effective in promoting C3S formation. The experimental results showed that samples were heated at an electric heating temperature(1500°C) and then further sintered with microwave for 30~60 min, tricalcium silicate could be formed with kilogram step. The new burning technique can greatly increase the forming speed of tricalcium silicate, MnO2, CuO and Ni2O3 could enhance the microwave sintering.

ELECTRICAL CONDUCTION IN SUBSTITUTED Li-FERRITES PREPARED BY MICROWAVE PROCESSING

2005 ◽  
Vol 19 (21) ◽  
pp. 1051-1055 ◽  
Author(s):  
MAMATA MAISNAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
CHANDRA PRAKASH ◽  
L. RADHAPIYARI DEVI ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lattice Constant ◽  
Electrical Conduction ◽  
Spinel Structure ◽  
Single Phase ◽  
Microwave Sintering ◽  
Microwave Processing ◽  
Conventional Sintering

Samples with representative formula Li 0.45 Ni 0.1 Mn 0.1 Fe 2.35 O 4 have been sintered by conventional sintering technique and microwave sintering technique. Both the samples showed single-phase with spinel structure. The lattice constant for the microwave sintered (MS) sample showed a lower value than the conventionally sintered (CS) sample. The density of the MS sample has been found to be higher than the CS sample. And MS sample showed a higher value of resistivity and activation energy compared to the CS sample. The possible mechanisms are discussed.

Apparent Activation Energy in High Frequency Microwave Sintering of Alumina Ceramic

2015 ◽  
Vol 1123 ◽  
pp. 391-396 ◽  
Author(s):  
I. Nyoman Sudiana ◽  
Seitaro Mitsudo ◽  
Shunsuke Inagaki ◽  
La Ode Ngkoimani ◽  
Usman Rianse ◽  
...  
Keyword(s):  
Activation Energy ◽  
Apparent Activation Energy ◽  
High Frequency ◽  
Driving Force ◽  
Microwave Sintering ◽  
High Frequencies ◽  
Conventional Sintering ◽  
Series Of Experiments ◽  
High Frequency Microwave ◽  
Sintering Method

The observed enhancements in the high frequency microwave processing alumina compared to those in conventional method at the same sintering temperatures have been studied. Some possible mechanisms responsible for the enhancements were investigated and are discussed in this paper. The enhancements could be associated with the increase either in driving force or in apparent activation energy of diffusion. An experiment to estimate the driving force of sintering is not easy to perform because the force depends not only on the density and grain size but also on the electric field in the materials. Therefore, a series of experiments to estimate the apparent activation energy were performed in high frequencies microwave and in conventional sintering method, as well. It was observed that the apparent activation energy in conventional sintering was much lower than that of microwave sintering. These activation energy values suggested that diffusion rate in microwaves sintering was faster, which led to the higher densification.

Ti-Ni Phase Diagram with Applied Stress

1993 ◽  
Vol 311 ◽  
Author(s):  
A.Peter Jardine
Keyword(s):  
Thin Film ◽  
Phase Diagram ◽  
Single Phase ◽  
Phase Evolution ◽  
The Other ◽  
Β Phase ◽  
The Stability ◽  
Tini Phase ◽  
Rich Side

ABSTRACTThe role of stress on the phase evolution of thin-film TiNi has not been investigated and may play an important role in the phase evolution of thin film TiNi. In this paper, a preliminary set of phase diagrams for Ni-Ti at different pressures are presented relating the stability of the stoichiometric TiNi phase to the other well-documented intermetallics TiNi3 and NiTi2. It is found that for sufficient pressure of the order of a GPa, the region where NiTi (β) phase is single phase shifts towards the Ti-rich side of the diagram. The implications on the annealing of TiNi thin film is discussed.

Preparation of Rare-Earth Permanent Magnetic Strontium Ferrite by Microwave Sintering Process

2010 ◽  
Vol 177 ◽  
pp. 264-268 ◽  
Author(s):  
Han Han Jiang ◽  
Ming Lin Jin ◽  
Zhan Yong Wang ◽  
Qi Zhong Chen ◽  
Hui Chun Qian
Keyword(s):  
Rare Earth ◽  
Microwave Sintering ◽  
Magnetic Domain ◽  
Strontium Ferrite ◽  
Green Body ◽  
Sintering Process ◽  
Wet Milling ◽  
Conventional Sintering ◽  
Degree Of Orientation ◽  
Sintering Method

In this paper, the green body was prepared by pre-roasted material of strontium ferrite, adding 0.2 to 9% the rare earth additive, by wet milling and forming into pellets Φ30×10 mm under magnetic field. Then, the green body was sintered separately by microwave sintering (MS) method and conventional sintering (CS) technique. The results showed that: the strontium ferrite samples with the same magnetic properties Br and (BH) max were 420 ± 10mT and 33.0 ± 2 kJ/m 3) were synthesized by microwave sintering (MS) method against conventional sintering method, the sintering temperature and time were reduced 150~300°C and 5~6h. Therefore, microwave sintering method will significantly decrease energy consumption. Further analysis revealed that the major improvements in microwave sintering were the material microstructure, the grain size was significantly reduced, the magnetic domain short-range order was increased so that the degree of orientation was increased, and although the fusion was existed between grains, the grain boundaries did not disappear.

scholarly journals Development and Validation of a Novel Stability-Indicating Reversed-Phase High-Performance Liquid Chromatography Method for Assay of Loratadine and Determination of Its Related Compounds

2010 ◽  
Vol 93 (3) ◽  
pp. 891-903 ◽  
Author(s):  
Jun Lu ◽  
Yu-Chien Wei ◽  
Robert J Markovich ◽  
Abu M Rustum
Keyword(s):  
High Performance ◽  
Sodium Dodecyl ◽  
Active Pharmaceutical Ingredient ◽  
Reversed Phase ◽  
Hplc Method ◽  
Chromatography Method ◽  
Stability Indicating ◽  
The Stability ◽  
Related Compounds

Abstract Loratadine is an important active pharmaceutical ingredient used in a wide variety of prescription and over-the-counter products for the treatment and relief of allergy symptoms. A novel stability-indicating gradient ion-pair RP-HPLC method for assay of loratadine and determination of both of its degradation compounds and process impurities has been developed. This method can separate loratadine from its eight structurally related compounds; it can also separate all of the related compounds from each other in less than 20 min. The stability-indicating capability of this method has been demonstrated by analyzing aged stability samples of loratadine. A 15 cm 4.6 mm id YMC-Pack Pro C18 HPLC column was the primary column and a 15 cm 4.6 mm id SunFire C18 column has been identified as an alternate (truly equivalent) column for this method. This gradient method uses mobile phases consisting of acetonitrile and an aqueous solution of 10 mM sodium acetate and 5 mM sodium dodecyl sulfate at pH 5.5. The new HPLC method was validated according to International Conference on Harmonization guidelines and proved to be suitable for routine QC use.

Microstructure and Magnetic Properties of Microwave Sintered Ni0.5Zn0.5Fe2O4 Ferrite

2013 ◽  
Vol 328 ◽  
pp. 705-709
Author(s):  
Yuan Dong Peng ◽  
Qing Lin Xia ◽  
Li Ya Li ◽  
Ming Lou ◽  
Jing Zhi Hu ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Microwave Sintering ◽  
Initial Permeability ◽  
Soaking Time ◽  
X Ray ◽  
Intrinsic Coercivity ◽  
Conventional Sintering ◽  
Maximum Permeability ◽  
Sintering Method ◽  
Microstructure And Magnetic Properties

Ni0.5Zn0.5)Fe2O4 ferrite has been sintered via microwave irradiation. The structural, component and magnetic properties of NiZn ferrite was determined by SEM, X-ray powder diffraction (XRD) and automatic hysteresis loop magnetometer. Results showed that the material sintered by microwave energy at 1220°C for 20min had a high purity (Ni0.5Zn0.5)Fe2O4 phase. The sample obtained magnetic properties of intrinsic coercivity 222A/m, saturation magnetization 332mT, initial permeability 0.20mH/m and maximum permeability 0.58mH/m. Compared with conventional sintering method, microwave sintering of NiZn ferrite is more efficient and reducing soaking time.

ChemInform Abstract: Rapid Microwave Synthesis and Structural Phase Diagram of LnxY1-xMnO3.

ChemInform ◽  
2014 ◽  
Vol 45 (40) ◽  
pp. no-no
Author(s):  
Fred P. Marlton ◽  
Darren J. Goossens ◽  
Reyner White ◽  
Wayne D. Hutchison
Keyword(s):  
Phase Diagram ◽  
Microwave Synthesis ◽  
Structural Phase

scholarly journals Electrical and mechanical properties of Cu-CNT nanocomposites sintered by microwave technique

2018 ◽  
Vol 23 (4) ◽  
pp. 303-317 ◽  
Author(s):  
Marjan Darabi ◽  
Masoud Rajabi
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Microwave Sintering ◽  
Multiwall Carbon Nanotubes ◽  
Physical And Mechanical Properties ◽  
Copper Matrix ◽  
Conventional Sintering ◽  
Novel Method ◽  
Sintering Method ◽  
Multiwall Carbon

In this research, multiwall carbon nanotubes were dispersed in a copper matrix using a planetary ball mill. The mixed powders were compacted using a uniaxial hydraulic presser. A novel method of microwave sintering was applied to consolidate Cu-CNT nanocomposites Conventional sintering method was also used to sinter samples to investigate the effects of applied methods on the properties of the sample. Sintering time was reduced to 20 min using microwave sintering method. The morphology and phase analysis of nanocomposites were studied by FESEM and XRD. The physical and mechanical properties of Cu-CNT nanocomposites were characterized using electrical conductivity, bending strength, and micro-hardness. The results show that the mechanical properties of Cu-CNT nanocomposites are improved significantly by microwave route. The optimum hardness and bending strength were obtained for 4 vol. % CNT as an optimum amount of reinforcement.

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