Growth dominant co-precipitation process to achieve high coercivity at room temperature in CoFe/sub 2/O/sub 4/ nanoparticles

2002 ◽  
Vol 38 (5) ◽  
pp. 2640-2642 ◽  
Author(s):  
C.N. Chinnasamy ◽  
B. Jeyadevan ◽  
O. Perales-Perez ◽  
K. Shinoda ◽  
K. Tohji ◽  
...  
2005 ◽  
Vol 498-499 ◽  
pp. 624-629 ◽  
Author(s):  
Márcia Caldeira Brant ◽  
Felipe da Silva Possa ◽  
Fernando Soares Lameiras

Powders of Ce0.8Gd0.2O1.9 were synthesized by co-precipitation and amorphous citrate routes and their compositions and structures were compared. Co-precipitation process was carried out at room temperature, while amorphous citrate synthesis was performed at 60-70 °C. The powders obtained were calcined at 700 °C for 1 h. X-ray diffraction analyses showed that a single fluorite structure was formed by both synthesis techniques. Pellets from these powders were prepared by compaction at 30 kN/cm2 and sintered at 1593 °C in air. WDS analysis confirmed the homogeneity of the pellets. The sintered pellets obtained by amorphous citrate and by coprecipitation routes showed relative densities over 97 % of the theoretical density. These results indicated that the citrate amorphous route is an interesting and simple technique to prepare gadolinium-doped ceria powders with high sinterability.


2011 ◽  
Author(s):  
Darminto ◽  
Machida N. Cholishoh ◽  
Feby A. Perdana ◽  
Malik A. Baqiya ◽  
Mashuri ◽  
...  

2009 ◽  
Vol 79-82 ◽  
pp. 505-508
Author(s):  
Li Li ◽  
H. Zhao ◽  
Wei Wang ◽  
F.F. Nie

The magnetic Fe3O4 nanoparticles had been synthesized by co-precipitation process and surface treatment by silane coupling agent (KH570). The magnetic Fe3O4/PMMA nanocomposite films were prepared by blend method, and the chemical structure, mechanical properties, surface morphology and the biocompatibility of the nanocomposite films were studied in this work. The magnetic Fe3O4 nanoparticles were well dispersed in the Fe3O4/PMMA nanocomposite films. The strength of the nanocomposite films, as well as the strain, decreased first and then increased with the increasing of the nanoparticles. The hemolytic ratio indicated that the nanocomposite films had a better blood compatibility.


RSC Advances ◽  
2016 ◽  
Vol 6 (54) ◽  
pp. 49228-49235 ◽  
Author(s):  
Chengwei Gao ◽  
Baojun Li ◽  
Ning Chen ◽  
Jie Ding ◽  
Qiang Cai ◽  
...  

Fe3O4/HNT@rGO composite (FHGC) was fabricated via a facile co-precipitation process, followed by heat treatment. For RhB and As5+removal, the high performance and easy separation of FHGC highlight its potential application in water treatment.


2016 ◽  
Vol 675-676 ◽  
pp. 69-72
Author(s):  
Krisana Chongsri ◽  
Wanichaya Mekprasart ◽  
Wisanu Pecharapa

In this work, we reported the preparation of F-doped ZnO nanoparticles by facile precipitation process using zinc nitrate and ammonium fluoride as starting precursors for Zn and F, respectively dissolved in deionized water. The precursor solution was prepared at various fluoride composition ranging from 1-5 wt%. The as-precipitated powders were calcined at different temperature from 500 °C to 700 °C for 2 h. Effect of calcination temperature and fluoride concentration on structural, morphologies, optical and electrical properties were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis spectroscopy, respectively. XRD results indicated the complete formation of hexagonal wurtzite structure of ZnO. SEM micrographs showed the agglomeration for each sample that noticeably influenced by fluoride content.


2021 ◽  
Vol 317 ◽  
pp. 119-124
Author(s):  
Sabiu Said Abdullahi ◽  
Garba Shehu Musa Galadanci ◽  
Norlaily Mohd Saiden ◽  
Josephine Ying Chyi Liew

The emergence of Dilute Magnetic Semiconductors (DMS) with a potentials for spintronic application have attracted much researches attention, special consideration has been given to ZnO semiconductor material due to its wide band gap of 3.37 eV, large exciting binding energy of 60 meV, moreover, its ferromagnetic behavior at room temperature when doped with transition metals. MxZn1-xO (M = Fe or Ni) nanoparticles were synthesized by microwave assisted synthesis method calcined at 600°C. The structural, morphological and magnetic properties of these nanoparticles were studied using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Vibrating Sample Magnetometer (VSM) respectively. Single phase Wurtzite hexagonal crystal structure was observed for the undoped and Fe doped ZnO nanoparticles with no any impurity, whereas Ni doped ZnO nanoparticles shows the formation of NiO impurities. The magnetic measurement reveals a diamagnetic behavior for the undoped ZnO meanwhile a clear room temperature ferromagnetism was observed for both Fe and Ni doped ZnO. Fe doped ZnO present a high saturation magnetization compared to Ni doped ZnO. However, Ni doped ZnO present high coercivity. The research was confirmed that Fe doped ZnO material will be good material combination for spintronic applications.


2003 ◽  
Vol 47 (1) ◽  
pp. 41-48 ◽  
Author(s):  
J. Duan ◽  
N.J.D. Graham ◽  
F. Wilson

The coagulation of a model seawater-humic acid solution with a hydrolysis metal salt (FeCl3) has been studied by monitoring floc size, solution pH, and zeta potential. The kinetic features of the orthokinetic coagulation have been demonstrated in relation to coagulant dosages, solution pH and zeta potential. Humic acid removal and floc charge reduction increased with coagulant dosage. Adjusting the solution pH prior to coagulation had a substantial effect on the treatment performance. By pH adjustment to pH 6, the greatest humic acid removal (by coagulation and subsequent membrane filtration) and the largest floc size was achieved at a FeCl3 dosage of 200 mmol l−1. It is believed that the coagulation is characterised by competition between OH- ions and humic acid for ferric ions in the co-precipitation process. In acidic pH, where the concentration of OH- ions is low, humic acid molecules may compete more favourably for bonding sites in the co-precipitation, which leads to a more compact precipitation and a higher overall humic acid removal.


2004 ◽  
Vol 03 (06) ◽  
pp. 829-837
Author(s):  
SOON-JONG JEONG ◽  
JUNG-HYUK KOH ◽  
DONG-YOON LEE ◽  
JAE-SEOK LEE ◽  
MUN-SU HA ◽  
...  

This study presents the synthesis of nano-oxide-added Ag/Pd powders and its properties tolerable at temperatures above 1100°C for an electrode material utilized in multilayer ceramic devices. The powders of xAg/yPd powder around core cell TiO 2 were formed in a co-precipitation process of Ag and Pd in nano-oxide-dispersed solution, where Ag and Pd precursors are melted in HNO 3 acid. Reaction between ceramic and electrode layers with nanoparticle oxide powder allows internal stress to reduce and mechanical bonding strength to increase due to anchor effect. The densification of the nano-oxide-added electrode paste followed the TiO 2 solid state diffusion-controlled mechanism upon sintering process. The mechanical bonding strength and electrical conductivity were measured after sintering the electrode-printed sheets. As a result, very high adhesive strength over the piezoelectric ceramics' fracture strength and good electrical conductivity of more than 104/Ωcm could be obtained in the multilayer ferroelectric structure which is a form of stacking ceramics layer and electrode layer containing nanoparticles.


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