Morphology of as-precipitated and dried powders in the PLZT system

1986 ◽  
Vol 44 ◽  
pp. 838-839
Author(s):  
R. W. Schwartz ◽  
D. A. Payne
Keyword(s):  
Freeze Drying ◽  
Ammonium Hydroxide ◽  
Ph Control ◽  
Continuous Reactor ◽  
Powder Particle Size ◽  
Oxide Ceramic ◽  
Chemical Preparation ◽  
Electro Optic ◽  
Particle Size And Morphology ◽  
Size And Morphology

High quality ceramic products, such as transparent electro-optic materials, require better control of chemical composition, powder particle size and morphology, than is offered by conventional mixed-oxide ceramic processing methods. Chemical preparation procedures can be used to prepare powders with the required characteristics of controlled size and morphology.Precipitated hydroxides in the PLZT system (lead lanthanum zirconium titanate) were prepared in a constant volume continuous reactor, following a procedure suggested by Murata, which uses nitrate and chloride precursors, and ammonium hydroxide for pH control. After washing with deionized water, the powders were dried by either spray-drying or freeze-drying in liquid nitrogen.

Solution-SBR Powders

1976 ◽  
Vol 49 (1) ◽  
pp. 126-139
Author(s):  
D. N. Schulz ◽  
L. E. Calihan ◽  
D. P. Tate
Keyword(s):  
Powder Particle Size ◽  
Factors Affecting ◽  
Molecular Weights ◽  
Bound Rubber ◽  
Powder Blends ◽  
Powder Particles ◽  
Filler Dispersion ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Powdered Rubber

Abstract This paper describes the advantageous cross-fertilization of solution-masterbatch technology and powdered-rubber processing. A nonlatex method has been developed for the preparation of free-flowing solution-SBR powders. The factors affecting powder particle size and morphology have been identified. Optimization of the preparative variables has resulted in dry-blendable solution-SBR powders. As a consequence of a low shear history, the solution-SBR powder blends show distinctive rubber-filler, rheological, and physical properties. For example, unvulcanized solution-SBR powder compounds evince higher molecular weights and lower bound-rubber contents than conventional mixes. Yet, the microscopic filler dispersion of these two types of compounds appears similar. Uncured solution-SBR powder blends also exhibit stiffer rheological behavior than conventional mixes. Furthermore, this stiffness tends to persist in the vuleanizates derived from these powdered compounds. Vulcanizate excellence depends primarily upon fineness of the powder particles and absence of free filler. Conditions have been found which permit the direct ribbon extrusion of tire tread, without prior compacting or milling. Conventional single-screw ribbon- tread extruders are sufficient to produce treads of high quality.

Investigation on Feedstock Preparation for Micro-Cemented Carbide Injection Molding

2018 ◽  
Vol 18 (2) ◽  
pp. 96-102
Author(s):  
Abdolali Fayyaz ◽  
Norhamidi Muhamad ◽  
Abu Bakar Sulong
Keyword(s):  
Flow Behavior ◽  
Flow Characteristics ◽  
High Viscosity ◽  
Cemented Carbide ◽  
Solid Loading ◽  
Powder Particle Size ◽  
Powder Particles ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Feedstock Preparation

Abstract This research was focused on mixing of submicron cemented carbide (WC-Co-VC) powder and binder. WC-Co-VC powder particle size and morphology were analyzed by laser diffraction and field emission scanning electron microscopy. The WC-Co-VC powder was kneaded with a paraffin wax based binder system. Based on critical solid loading, the feedstock with different solid loadings between 49 to 51 vol.% was prepared. Finally, the flow behavior of different feedstocks was investigated. Morphology of powder revealed that the particles of powder are slightly agglomerated and irregular in shape. The result of mixing indicted that the torque value increases as the solid loading increase from 49 vol.% to 51 vol.%. The feedstock exhibited homogeneity and the powder particles are homogenously coated with binder. The feedstock with solid loading of 51 vol.% is sensitive to temperature and showed high viscosity values. The feedstock with solid loadings of 49 and 50 vol.% had good compatibility and flow characteristics.

Preparation of fine multicomponent oxide ceramic powder by a combustion synthesis process

1994 ◽  
Vol 9 (8) ◽  
pp. 1997-2004 ◽  
Author(s):  
Yangsheng Zhang ◽  
Gregory C. Stangle
Keyword(s):  
Ceramic Powder ◽  
Synthesis Process ◽  
Maximum Temperature ◽  
Oxide Ceramic ◽  
Multicomponent Oxide ◽  
Powder Packing ◽  
Ferrite Material ◽  
Maximum Reaction ◽  
Particle Size And Morphology ◽  
Size And Morphology

An important, rather novel procedure for the synthesis of submicron crystalline multicomponent oxide ceramic powders has been studied. The synthesis of CuFe2O4 powder, a ferrite material, has been used as a model system for understanding the synthesis process. The effect of the fuel content, powder packing, and surface heat loss has been investigated in terms of the maximum reaction temperature and reaction period, phase formation, and particle size and morphology. It has been shown that the maximum temperature and reaction period can be tailored to produce different phases. The submicron features of the synthesized powders are indicated by the large surface area values obtained from BET measurement.

Direct manipulation of particle size and morphology of ordered mesoporous silica by flow synthesis

RSC Advances ◽  
2015 ◽  
Vol 5 (18) ◽  
pp. 13331-13340 ◽  
Author(s):  
T. N. Ng ◽  
X. Q. Chen ◽  
K. L. Yeung
Keyword(s):  
Particle Size ◽  
Mesoporous Silica ◽  
Hollow Spheres ◽  
Ordered Mesoporous Silica ◽  
Direct Manipulation ◽  
Flow Synthesis ◽  
Precise Control ◽  
Ordered Mesoporous ◽  
Particle Size And Morphology ◽  
Size And Morphology

Flow-synthesis of mesoporous silica allows deliberate and precise control over the size and shapes and enables the preparation of complex microstructures (i.e., hollow spheres).

Preparation of High-Purity Ultrafine α-Al2O3 by Solid-State Reaction at Room Temperature

2008 ◽  
Vol 368-372 ◽  
pp. 683-685
Author(s):  
Cheng Wei Hao ◽  
Bo Lin Wu ◽  
Ji Yan Li
Keyword(s):  
Solid State ◽  
High Purity ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Raw Materials ◽  
Phase Particle ◽  
Phase Transformation Temperature ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Α Al2o3

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.

scholarly journals Synthesis and Characterization of a Fe3O4@PNIPAM-Chitosan Nanocomposite and Its Potential Application in Vincristine Delivery

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1704
Author(s):  
Cynthia N. Hernández-Téllez ◽  
Ana G. Luque-Alcaraz ◽  
Maribel Plascencia-Jatomea ◽  
Hiram J. Higuera-Valenzuela ◽  
Mabeth Burgos-Hernández ◽  
...  
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Release Kinetics ◽  
Magnetic Core ◽  
Systematic Evaluation ◽  
Solution Temperature ◽  
Core Shell ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Thermomagnetic Properties ◽  
Release Model

In this research, we conducted a systematic evaluation of the synthesis parameters of a multi-responsive core-shell nanocomposite (Fe3O4 nanoparticles coated by poly(N-isopropylacrylamide) (PNIPAM) in the presence of chitosan (CS) (Fe3O4@PNIPAM-CS). Scanning electron microscopy (SEM) was used to follow the size and morphology of the nanocomposite. The functionalization and the coating of Fe3O4 nanoparticles (Nps) were evaluated by the ζ-potential evolution and Fourier Transform infrared spectroscopy (FTIR). The nanocomposite exhibited a collapsed structure when the temperature was driven above the lower critical solution temperature (LCST), determined by dynamic light scattering (DLS). The LCST was successfully shifted from 33 to 39 °C, which opens the possibility of using it in physiological systems. A magnetometry test was performed to confirm the superparamagnetic behavior at room temperature. The obtained systems allow the possibility to control specific properties, such as particle size and morphology. Finally, we performed vincristine sulfate loading and release tests. Mathematical analysis reveals a two-stage structural-relaxation release model beyond the LCST. In contrast, a temperature of 25 °C promotes the diffusional release model. As a result, a more in-depth comprehension of the release kinetics was achieved. The synthesis and study of a magnetic core-shell nanoplatform offer a smart material as an alternative targeted release therapy due to its thermomagnetic properties.

scholarly journals Dehumidified Air-Assisted Spray-Drying of Cloudy Beetroot Juice at Low Temperature

2021 ◽  
Vol 11 (14) ◽  
pp. 6578
Author(s):  
Aleksandra Jedlińska ◽  
Alicja Barańska ◽  
Dorota Witrowa-Rajchert ◽  
Ewa Ostrowska-Ligęza ◽  
Katarzyna Samborska
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Spray Drying ◽  
Low Temperatures ◽  
Beetroot Juice ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Tapped Density ◽  
Lower Loss ◽  
Better Than

This paper discusses the physicochemical properties of powders obtained by spray drying of cloudy beetroot juice, using dehumidified air in variants with or without carriers. The inlet air temperature was 130 °C or 90 °C, and the addition of the carriers was at a ratio of juice to carrier solids of 3:2. In the obtained powders, the following physicochemical properties were determined: water content and water activity, apparent density, loose and tapped density, porosity, flowability, particle size and morphology, and the content and retention of betalains. It was possible to dry cloudy beetroot juice without the use of carriers at low temperatures (90 or 130 °C). The 100% beetroot powders were characterized by satisfactory physicochemical properties, often better than those with carriers (including lower hygroscopicity and higher color saturation and yield). A lower loss of betalains was found for the powders with the addition of carriers. The best process yields were obtained for the powder without carriers at 130 °C and 90 °C.

Synthesis and Characterization of Calcium Tartrate Dihydrate Nanoparticles

2015 ◽  
Vol 14 (04) ◽  
pp. 1550013 ◽  
Author(s):  
Urvisha Tarpara ◽  
Poorvesh Vyas ◽  
Mihir J. Joshi
Keyword(s):  
Average Crystallite Size ◽  
Powder Xrd ◽  
Xrd Pattern ◽  
Crystalline Materials ◽  
Transmission Electron ◽  
Calcium Tartrate ◽  
Particle Size And Morphology ◽  
Wet Chemical ◽  
Size And Morphology

Calcium tartrate finds various applications. In the present study, calcium tartrate nanoparticles were synthesized by wet chemical method using surfactant mediated approach. The powder XRD pattern revealed the typical broadening of peaks indicating the nanostructured nature. The average crystallite size was calculated by applying the Scherrer's formula to powder XRD pattern and was found in the range of 22.8–23.9 nm. The particle size and morphology of the synthesized nanoparticles was confirmed by using transmission electron microscopy (TEM). FTIR spectroscopy was used to confirm the presence of various functional groups. From TGA, it was found that calcium tartrate nanoparticles remained stable up to 120°C and were having two water molecules associated with them. The results are compared with the bulk crystalline materials available in the literature.

Synthesis and Properties of (Bi0.5Na0.5)TiO3 Powders by Hydrothermal Method

2007 ◽  
Vol 336-338 ◽  
pp. 140-142
Author(s):  
Jun Jie Hao ◽  
Xiao Hui Wang ◽  
Shi Yun Lin ◽  
Long Tu Li
Keyword(s):  
Particle Size ◽  
Hydrothermal Method ◽  
Single Phase ◽  
Piezoelectric Ceramics ◽  
Treatment Temperature ◽  
Lead Free ◽  
Excellent Candidate ◽  
Traditionally Prepared ◽  
Particle Size And Morphology ◽  
Size And Morphology

Na0.5Bi0.5TiO3 (NBT) is considered to be an excellent candidate for lead-free piezoelectric ceramics. In this study, we propose a hydrothermal method for the preparation of single phase NBT powder at relatively low treatment-temperature. The particle size and morphology of the synthesized powders were examined by SEM. The powders were further pressed into disk and sintered at 1120°C/2h in air, and its properties and microstructure were compared with traditionally prepared samples.

Sign in / Sign up

Export Citation Format

Share Document