Preparation of Nanocrystalline Ba3(Ca1.18Nb1.82)O9-δ Powder with Sol-Gel Auto-Ignition Synthesis Process

2007 ◽  
Vol 280-283 ◽  
pp. 631-634 ◽  
Author(s):  
Xin Tai Su ◽  
Qing Zhi Yan ◽  
Chang Chun Ge

Ba3(Ca1.18Nb1.82)O9-d (BCN18) powder was synthesized using a wet chemical method from mixtures of all water-soluble compounds including Ba, Ca and Nb-citrate. It has been found that NH4NO3 in the initial solutions plays an important role in controlling the enthalpy of low temperature combustion process as well as the gel decomposition temperature. Further steps include evaporating, drying and calcinating. The obtained gels were characterized by TG-DSC, and the powder was characterized with XRD, TEM and BET. The experimental results have indicated that the heating temperature was only 800°C for synthesizing the powder and the average particle size was only about 40-50 nm. Furthermore it was found that a pure BCN18 phase with complexperovskite structure was formed at 800°C, which was about 800°C lower than that of the traditional solid-reaction method. So it is more practical and more superior to the traditional solid-reaction method and the present wet-chemical method in alcohol salt system reported in literature.

2002 ◽  
Vol 720 ◽  
Author(s):  
N N Ghosh

AbstractIn the present investigation, an attempt has been made to establish a new chemical route for synthesis of the nanostructured mixed oxide ferrite powders. By using this chemical method a variety of ferrite powders having spinel structure and doped with Co, Ni, Mn, Zn etc has been prepared. In this method nitrate salts of the different metals were used as starting materials. The aqueous solutions of the metal nitrates were mixed according to the molar ration of the compositions. Then the mixtures were mixed with an aqueous solution of water soluble polymer (polyvinyl alcohol). This mixture after drying yield fluffy brown powders. These powders were then calcined at different temperatures ranging from 400 °C to 700 °C. Nanostructured powders were obtained from the thermal decomposition of the brown powders. The powders, prepared by calcinations at different temperatures, were characterized by using X-Ray diffraction analysis, IR spectroscopy, TGA/DTA, and TEM. It was observed that the average particle size of the powders are in nanometer scale with a narrow size distribution. The average particle size of the powders was increased with the increase of calcinations temperature.This chemical method has proved to provide a convenient process for the preparation of nanostructured ceramic powders at comparatively low temperatures and offers the potential of being a simple and cost-effective route.


2009 ◽  
Vol 19 (1) ◽  
pp. 33-38
Author(s):  
Tran Minh Thi

ZnS:Mn were prepared by wet chemical method with Mn doping concentration from 0 at% to 12 at%. The structure and particle size of the obtained powders were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and shown that all samples are single phase with sphalerite crystal structure and average particle size of about 5 - 7 nm. The dependence of Mn2+ ions doped concentration, and UV irradiation time on the luminescent intensity of ZnS:Mn nanocrystals was discussed.


2021 ◽  
Vol 09 ◽  
Author(s):  
Ozra Tabasi ◽  
Mahdi Roohi Razlighi ◽  
Mohammad Ali Darbandi

Background: Ferric carboxymaltose (FCM) formulation consists of iron–carbohydrate nanoparticles that iron– oxyhydroxide as a core is covered by carbohydrate shell. The present work provides an improved synthesis process of FCM as an intravenous iron active pharmaceutical ingredient. Methods: Water soluble FCM complex was prepared from the reaction of ferric hydroxide precipitation with an aqueous solution of oxidized maltodextrin (MD) at optimum temperature and pH conditions. A systematic approach was followed to obtain the optimal weight ratio of the maltodextrin/ferric chloride for FCM synthesis process with suitable-sized nanoparticles. Physical characterization of new synthesized ferric carboxymaltose (FCM-NP) was performed and established its equivalency with the reference product (Ferinject). Results: The size distribution of the whole nanoparticles determined by dynamic light scattering (DLS) was in the range of 15-40 nm with the average particle size 26 ± 6.6 and 25.8 ± 4.9 for FCM-NP and Ferinject, respectively. X-ray diffraction (XRD) results of FCM-NP and Ferinject indicated the Akaganeite structure of iron-oxyhydroxide. The iron content of particles (cores) measured by Atomic absorption spectroscopy (AAS) was almost equal for two formulations. The Fourier transform infrared (FTIR) spectra of Ferinject and FCM-NP were approximately similar. Conclusion: Various analytical methods including FTIR spectroscopy, XRD analysis, DLS technique, TEM, and AAS were employed. It was observed that the specifications of FCM-NP obtained by these analyses, were almost identical to those of Ferinject. Accordingly, the two formulations were considered comparable.


2020 ◽  
Vol 9 (1) ◽  
pp. 386-398 ◽  
Author(s):  
Mahmood S. Jameel ◽  
Azlan Abdul Aziz ◽  
Mohammed Ali Dheyab

AbstractPlatinum nanoparticles (Pt NPs) have attracted interest in catalysis and biomedical applications due to their unique structural, optical, and catalytic properties. However, the conventional synthesis of Pt NPs using the chemical and physical methods is constrained by the use of harmful and costly chemicals, intricate preparation requirement, and high energy utilization. Hence, this review emphasizes on the green synthesis of Pt NPs using plant extracts as an alternative approach due to its simplicity, convenience, inexpensiveness, easy scalability, low energy requirement, environmental friendliness, and minimum usage of hazardous materials and maximized efficiency of the synthesis process. The underlying complex processes that cover the green synthesis (biosynthesis) of Pt NPs were reviewed. This review affirms the effects of different critical parameters (pH, reaction temperature, reaction time, and biomass dosage) on the size and shape of the synthesized Pt NPs. For instance, the average particle size of Pt NPs was reported to decrease with increasing pH, reaction temperature, and concentration of plant extract.


2021 ◽  
Vol 11 (5) ◽  
pp. 2426
Author(s):  
Vladimir Promakhov ◽  
Alexey Matveev ◽  
Nikita Schulz ◽  
Mikhail Grigoriev ◽  
Andrey Olisov ◽  
...  

Currently, metal–matrix composite materials are some of the most promising types of materials, and they combine the advantages of a metal matrix and reinforcing particles/fibres. Within the framework of this article, the high-temperature synthesis of metal–matrix composite materials based on the (Ni-Ti)-TiB2 system was studied. The selected approaches make it possible to obtain composite materials of various compositions without contamination and with a high degree of energy efficiency during production processes. Combustion processes in the samples of a 63.5 wt.% NiB + 36.5 wt.% Ti mixture and the phase composition and structure of the synthesis products were researched. It has been established that the synthesis process in the samples proceeds via the spin combustion mechanism. It has been shown that self-propagating high-temperature synthesis (SHS) powder particles have a composite structure and consist of a Ni-Ti matrix and TiB2 reinforcement inclusions that are uniformly distributed inside it. The inclusion size lies in the range between 0.1 and 4 µm, and the average particle size is 0.57 µm. The obtained metal-matrix composite materials can be used in additive manufacturing technologies as ligatures for heat-resistant alloys, as well as for the synthesis of composites using traditional methods of powder metallurgy.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1714
Author(s):  
Paweł Wiśniewski

This study presents the general characteristics of binders used in precision casting of Nickel-based superalloys. Three groups of binders were described: resins, organic compounds, and materials containing nanoparticles in alcohol or aqueous systems. This study also includes literature reports on materials commonly used and those recently replaced by water-soluble binders, i.e., ethyl silicate (ES) and hydrolysed ethyl silicate (HES). The appearance of new and interesting solutions containing nano-alumina is described, as well as other solutions at the initial stage of scientific research, such as those containing biopolymers, biodegradable polycaprolactone (PCL), or modified starch. Special attention is paid to four binders containing nano-SiO2 intended for the first layers (Ludox AM, Ludox SK) and structural layers (EHT, Remasol) of shell moulds. Their morphology, viscosity, density, reactions, and electrokinetic potential were investigated. The binders were characterized by a high solid-phase content (>28%), viscosity, and density close to that of water (1–2 mPa·s) and good electrokinetic stability. The nanoparticles contained in the binders were approximately spherically shaped with an average particle size of 16–25 nm.


Ionics ◽  
2021 ◽  
Vol 27 (4) ◽  
pp. 1465-1475
Author(s):  
Ning Zhang ◽  
Ying Li ◽  
Yadan Luo ◽  
Zhen Yang ◽  
Jiayao Lu

RSC Advances ◽  
2016 ◽  
Vol 6 (60) ◽  
pp. 55546-55551 ◽  
Author(s):  
Shu-Qing Lv ◽  
Ya-Fei Pan ◽  
Pei-Bo Yang ◽  
Guang-Sheng Wang

By using a simple wet chemical method and hot-molding procedure, a kind of flexible film with enhance absorption properties based on binary cobalt nanochains/polyvinylidene fluoride (PVDF) hybrids has been successfully fabricated.


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