scholarly journals Development of optimum preparation conditions of Fe-deficient M-type Ca-Sr System hexagonal ferrites

2020 ◽  
Author(s):  
Ching-Chien Huang ◽  
Mo Chin-Chieh ◽  
Hsiao Tsung-Han ◽  
Lu Sheng-Han ◽  
Tai Yen-Hua ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Permanent Magnets ◽  
High Efficiency ◽  
Cobalt Content ◽  
Preparation Condition ◽  
Raw Material ◽  
Preparation Conditions ◽  
Typical Specimen ◽  
Specific Manifestation

Abstract In this work, an experiment was carried out to investigate the preparation condition of anosotropic Fe-deficient M-type Ca-Sr system ferrite with optimum magnetic and physical properties using the raw material Fe2O3 from steel industrial iron oxide waste. The compositions of the calcined ferrites were chosen according to the stoichiometry Ca1 − x−yLaxSryFe10.9CozO19, where x was varied between 0.05 and 0.85, y between 0 and 0.18, and z = 0. The effect of CaO, SiO2 and Co3O4 inter-additives on the Ca-Sr system ferrite was also discussed in order to obtain low-temperature sintered magnets. The optimum condition of making magnets and some properties of a typical specimen are as follows. The preparation condition: condition: composition Ca0.37La0.45Sr0.18Fe10.9Co0O19, calcination condition 1240 °C × 1hr in atmosphere, low-temperature sintering condition 1210 °C × 1hr in atmosphere, inter-additives Co3O4 = 1.85 wt%, CaCO3 = 1.7 wt%, SiO2 = 0.6 wt%, CaO/SiO2 = 1.59. The magnetic properties of Br=5425 Gauss, bHc=4320 Oe, iHc=4602 Oe and (BH)max=5.26 MGOe were obtained for Ca-Sr system hard magnets with relatively low cobalt content. The unremarkable steel industrial iron oxide waste is recycled produce high-end permanent magnets under output power < 1 kW, which will eventually be used in high-efficiency motors. This is a specific manifestation of "garbage turning into gold" and is one of the best models of circular economy.

scholarly journals Investigation on the La Replacement and Little Additive Modification of High-Performance Permanent Magnetic Strontium-Ferrite

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1034
Author(s):  
Ching-Chien Huang ◽  
Chin-Chieh Mo ◽  
Guan-Ming Chen ◽  
Hsiao-Hsuan Hsu ◽  
Guo-Jiun Shu
Keyword(s):  
High Performance ◽  
Single Phase ◽  
Permanent Magnets ◽  
High Efficiency ◽  
Cobalt Content ◽  
Preparation Condition ◽  
Milling Process ◽  
Experimental Parameters ◽  
La Substitution ◽  
Hard Magnets

In this work, an experiment was carried out to investigate the preparation condition of anisotropic, Fe-deficient, M-type Sr ferrite with optimum magnetic and physical properties by changing experimental parameters, such as the La substitution amount and little additive modification during fine milling process. The compositions of the calcined ferrites were chosen according to the stoichiometry LaxSr1-xFe12-2xO19, where M-type single-phase calcined powder was synthesized with a composition of x = 0.30. The effect of CaCO3, SiO2, and Co3O4 inter-additives on the Sr ferrite was also discussed in order to obtain low-temperature sintered magnets. The magnetic properties of Br = 4608 Gauss, bHc = 3650 Oe, iHc = 3765 Oe, and (BH)max = 5.23 MGOe were obtained for Sr ferrite hard magnets with low cobalt content at 1.7 wt%, which will eventually be used as high-end permanent magnets for the high-efficiency motor application in automobiles with Br > 4600 ± 50 G and iHc > 3600 ± 50 Oe.

Preparation of Coal-Based Activated Carbon and its Application for Methylene Blue Removal

2012 ◽  
Vol 253-255 ◽  
pp. 988-992
Author(s):  
Guo Zhuo Gong ◽  
Qiang Xie ◽  
Wen Fen Yang ◽  
Xin Yao
Keyword(s):  
Methylene Blue ◽  
Orthogonal Experiment ◽  
Preparation Condition ◽  
Raw Material ◽  
Activation Temperature ◽  
Surface Areas ◽  
Preparation Conditions ◽  
Adsorption Capacities ◽  
Acid Washing ◽  
Mb Adsorption

In accordance with an orthogonal experiment design, a series of ACs for methylene blue (MB) removal had been prepared in the presence of small amounts of KOH in raw material combined with delicate acid washing after carbonization and before steam activation. ACs were characterized, and their adsorption capacities for MB were determined as well. It was found that it was feasible to regulate and optimize pore structure in coal-based ACs by tuning preparation conditions concisely and properly, and the MB adsorption capacities were linearly correlated with their specific surface areas. Based on statistic analysis, it was revealed that among the four process variables studied for the sorbent prepared in this work, the activation temperature was found to be the most significant one for the MB adsorption capacity, the next ones were the activation time, the flow rate of water vapor and the amount of KOH, and an optimized preparation condition was figured out.

scholarly journals Preparation and Characterization of Sr1−xNdxFe12O19 Derived from Steel-Waste Product via Mechanical Alloying

2016 ◽  
Vol 846 ◽  
pp. 403-409 ◽  
Author(s):  
Noruzaman Daud ◽  
Raba’ah Syahidah Azis ◽  
Mansor Hashim ◽  
Khamirul Amin Matori ◽  
Hassan Jumiah ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Iron Oxide ◽  
Mechanical Alloying ◽  
Doping Concentration ◽  
Magnetic Particle ◽  
Permanent Magnets ◽  
Waste Product ◽  
Fine Powder ◽  
Raw Material ◽  
Temperature Separation

Steel waste product had been used as the main source of raw material in the preparation of permanent magnets ferrites. Steel waste product is an impure material that contains the iron oxide and impurities. The steel waste product is a form of flakes is grinding for several hours to form a fine powder. The iron oxide powder is separated from magnetic and non-magnetic particle using magnetic particle separation. The magnetic particle was again been purified by using the Curie temperature separation technique. The magnetic powder was carried out from the purification and oxidize at 500 °C for 6 hours at 2 °C/ mins to form the hematite, Fe2O3, used as a raw powder to prepare SrFe12O19. Microstructure of Nd-doped strontium ferrites, Sr1-xNdxFe12O19, with x = 0.0, 0.1, 0.2, 0.3, 0.4 and 0.5, were prepared through a mechanical alloying technique. Several characterizations have been done, such as X-ray Diffraction (XRD) and Field emission scanning electron microscopy (FESEM). The magnetic properties of coercivity (Hc) and the energy product BHmax of samples are carried out. The magnetic properties of samples were investigated with an expectation of enhancing the magnetic properties by substitutions of Nd3+ ions on Fe3+ ion basis sites. The saturation magnetization Ms revealed magnetic behavior with respect to Nd3+ doping concentration, showing a decrease. The coercivity Hc increased with increasing Nd3+ doping concentration.

Utilizing the Oxygen Carrier Property of Cerium Iron Oxide for the Low-Temperature Synthesis of 1,3-butadiene from 1-butene

2021 ◽  
Author(s):  
Aswathy T. Venugopalan ◽  
Prabu Kandasamy ◽  
Pranjal Gogoi ◽  
Jha Ratneshkumar ◽  
Raja Thirumalaiswamy
Keyword(s):  
Iron Oxide ◽  
Low Temperature ◽  
Oxygen Carrier ◽  
Low Temperature Synthesis ◽  
Temperature Synthesis

scholarly journals Preparation and application of carbon and hollow TiO2 microspheres by microwave heating at a low temperature

e-Polymers ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 200-209
Author(s):  
Caiyun Zhang ◽  
Chunhong Li ◽  
Bolin Ji ◽  
Zhaohui Jiang
Keyword(s):  
Low Temperature ◽  
Microwave Heating ◽  
Raw Material ◽  
Carbon Microspheres ◽  
Microwave Assisted ◽  
The Core ◽  
Good Crystallinity ◽  
Carbon Core ◽  
Microwave Assisted Method ◽  
Uniform Particle Size

Abstract A fast, simple, and energy-saving microwave-assisted approach was successfully developed to prepare carbon microspheres. The carbon microspheres with a uniform particle size and good dispersity were prepared using glucose as the raw material and HCl as the dehydrating agent at low temperature (90°C) in an open system with the assistance of microwave heating. The carbon microspheres were characterized by elemental analysis, XRD, SEM, FTIR, TG, and Raman. The results showed that the carbon microspheres prepared under the condition of 18.5% (v/v) HCl and heating for 30 min by microwave had a narrow size distribution. The core–shell structure of the carbon core and TiO2 shell was prepared with (NH4)2TiF6, H3BO3 using the microwave-assisted method. The hollow TiO2 microspheres with good crystallinity and high photocatalytic properties were successfully prepared by sacrificing the carbon microspheres.

scholarly journals Biochar Improves Maize Growth but Has a Limited Effect on Soil Properties: Evidence from a Three-Year Field Experiment

2021 ◽  
Vol 13 (7) ◽  
pp. 3617
Author(s):  
Agnieszka Medyńska-Juraszek ◽  
Agnieszka Latawiec ◽  
Jolanta Królczyk ◽  
Adam Bogacz ◽  
Dorota Kawałko ◽  
...  
Keyword(s):  
Low Temperature ◽  
Field Experiment ◽  
Soil Properties ◽  
High Efficiency ◽  
Crop Yields ◽  
Temperate Climate ◽  
Soil Conditions ◽  
Maize Growth ◽  
Chemical Soil ◽  
Physical And Chemical

Biochar application is reported as a method for improving physical and chemical soil properties, with a still questionable impact on the crop yields and quality. Plant productivity can be affected by biochar properties and soil conditions. High efficiency of biochar application was reported many times for plant cultivation in tropical and arid climates; however, the knowledge of how the biochar affects soils in temperate climate zones exhibiting different properties is still limited. Therefore, a three-year-long field experiment was conducted on a loamy Haplic Luvisol, a common arable soil in Central Europe, to extend the laboratory-scale experiments on biochar effectiveness. A low-temperature pinewood biochar was applied at the rate of 50 t h−1, and maize was selected as a tested crop. Biochar application did not significantly impact the chemical soil properties and fertility of tested soil. However, biochar improved soil physical properties and water retention, reducing plant water stress during hot dry summers, and thus resulting in better maize growth and higher yields. Limited influence of the low-temperature biochar on soil properties suggests the crucial importance of biochar-production technology and biochar properties on the effectiveness and validity of its application in agriculture.

scholarly journals Effect of SnO2 Colloidal Dispersion Solution Concentration on the Quality of Perovskite Layer of Solar Cells

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 591
Author(s):  
Keke Song ◽  
Xiaoping Zou ◽  
Huiyin Zhang ◽  
Chunqian Zhang ◽  
Jin Cheng ◽  
...  
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
High Efficiency ◽  
Surface Condition ◽  
Perovskite Solar Cells ◽  
Colloidal Dispersion ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Perovskite Layer ◽  
Dispersion Solution

The electron transport layer (ETL) is critical to carrier extraction for perovskite solar cells (PSCs). Moreover, the morphology and surface condition of the ETL could influence the topography of the perovskite layer. ZnO, TiO2, and SnO2 were widely investigated as ETL materials. However, TiO2 requires a sintering process under high temperature and ZnO has the trouble of chemical instability. SnO2 possesses the advantages of low-temperature fabrication and high conductivity, which is critical to the performance of PSCs prepared under low temperature. Here, we optimized the morphology and property of SnO2 by modulating the concentration of a SnO2 colloidal dispersion solution. When adjusting the concentration of SnO2 colloidal dispersion solution to 5 wt.% (in water), SnO2 film indicated better performance and the perovskite film has a large grain size and smooth surface. Based on high efficiency (16.82%), the device keeps a low hysteresis index (0.23).

High-Efficiency Low-Temperature ZnO Based Perovskite Solar Cells Based on Highly Polar, Nonwetting Self-Assembled Molecular Layers

2017 ◽  
Vol 8 (5) ◽  
pp. 1701683 ◽  
Author(s):  
Randi Azmi ◽  
Wisnu Tantyo Hadmojo ◽  
Septy Sinaga ◽  
Chang-Lyoul Lee ◽  
Sung Cheol Yoon ◽  
...  
Keyword(s):  
Solar Cells ◽  
Low Temperature ◽  
High Efficiency ◽  
Perovskite Solar Cells ◽  
Self Assembled ◽  
Molecular Layers

Low Temperature Silicon Oxidation With Electron Cyclotron Resonance Oxygen Plasma

1991 ◽  
Vol 235 ◽  
Author(s):  
K. T. Sung ◽  
S. W. Pang
Keyword(s):  
Low Temperature ◽  
Microwave Power ◽  
Cyclotron Resonance ◽  
Oxygen Plasma ◽  
Permanent Magnets ◽  
Electron Cyclotron Resonance ◽  
Electron Cyclotron ◽  
Rf Power ◽  
Source Distance ◽  
Ecr Source

ABSTRACTSilicon was oxidized at low temperature with an oxygen plasma generated by an electron cyclotron resonance (ECR) source. The ECR source utilized a multicusp magnetic field formed by permanent magnets. Microwave power at 2.45 GHz was applied to the source and if power at 13.56 MHz was applied to the sample stage. Si oxidation was studied as a function of source distance, pressure, microwave power, and rf power. The oxide thickness increases with microwave and rf power but decreases with source distance. The oxidation rate increases with pressure up to 12 mTorr, men decreases at higher pressure. The relative emission intensities in the plasma monitored using optical emission spectroscopy showed similar dependence on the source distance and microwave power. Oxidation temperature was estimated to be <100°C. Using ellipsometry and X-ray photoelectron spectroscopy, the oxidized films were found to be close to that of thermal oxide with refractive index at 1.45 and oxygen to silicon ratio of 2. From the current-voltage and capacitance-voltage measurements, the breakdown fields of these oxide films were 6.3 MV/cm and the fixed charge densities were 7×1010 cm−2.

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