scholarly journals ZnTiO3 ceramic nanopowder microstructure changes during compaction

2013 ◽  
Vol 45 (2) ◽  
pp. 209-221
Author(s):  
N. Labus ◽  
J. Krstic ◽  
S. Markovic ◽  
D. Vasiljevic-Radovic ◽  
M.V. Nikolic ◽  
...  
Keyword(s):  
Particle Size ◽  
Pore Size ◽  
Size Distribution ◽  
Mercury Porosimetry ◽  
Critical Diameter ◽  
Nitrogen Adsorption ◽  
Powder Particle Size ◽  
Scanning Electron Micrographs ◽  
Force Microscopy ◽  
Scanning Electron

ZnTiO3 nanopowder as a constitutive component in compact production was primarily characterized. Scanning electron micrographs of as received powder were recorded. Mercury porosimetry and nitrogen adsorption were also performed on loose powder. Particle size distribution in a water powder suspension was determined with a laser particle size analyser. Compaction was performed on different pressures in a range from 100 to 400 MPa using the uniaxial double sided compaction technique without binder and lubricant. Micrographs of compacted specimens were obtained using scanning electron microscopy and atomic force microscopy. Pore size distribution was also determined by mercury porosimetry and nitrogen adsorption. Results revealed that with increasing pressure during compaction interagglomerate pores diminish in size until they reach some critical diameter related to the intra-agglomerate pore size.

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

Tape Casting of BaTiO3

1984 ◽  
Vol 40 ◽  
Author(s):  
J. B. Blum ◽  
W. R. Cannon
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Glass Plate ◽  
Tape Casting ◽  
Phosphate Ester ◽  
Powder Particle Size ◽  
Drying Method ◽  
Ultrasonic Dispersion ◽  
The Past

AbstractFor the past two years we have been investigating the tape casting of BaTiO3 Specifically we have been interested in developing a useful tape casting formulation and procedure and in studying the effects of powder particle size distribution and dispersion processes on the forming of BaTiO3 tapes.The formulation we have developed is non-aqueous. An MEKethanol mixture is the solvent and an acrylic binder is used. Two dispersants are being used, a phosphate ester and Menhaden fish oil. Ultrasonic dispersion was found to be effective in breaking up weak powder agglomerates. We have found it important to add the dispersant before adding other organic components to obtain the best dispersion and strongest tapes. The drying method is also important to tape strength. The strongest tapes resulted when the tape was removed from the glass plate soon after casting. We have also demonstrated that for forming purposes a wide particle size distribution is preferred.

scholarly journals Ball-milling effect on Indonesian natural bentonite for manganese removal from acid mine drainage

2018 ◽  
Vol 156 ◽  
pp. 03046 ◽  
Author(s):  
Widyawanto Prastistho ◽  
Winarto Kurniawan ◽  
Hirofumi Hinode
Keyword(s):  
Particle Size ◽  
Acid Mine Drainage ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mine Drainage ◽  
Nitrogen Adsorption ◽  
Exchange Capacity ◽  
Manganese Removal ◽  
Acid Mine ◽  
Adsorption Desorption

The influences of mechanical milling on Indonesian Natural Bentonite (INB) characteristics and manganese (Mn) removal from acid mine drainage (AMD) were investigated. The INB characteristics were observed by scanning electron microscope (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption for specific surface area (SSA) and microporosity measurement, cation exchange capacity (CEC) and particle size distribution (PSD) analyzer. Four minutes milling with frequency 20 Hz on INB caused morphological change which showed more crumbled and destructed particle, lost the (001) peak but still retained the (100) peak that indicated delamination of montmorillonite mineral without breaking the tetrahedral-octahedral-tetrahedral (T-O-T) structure, rose the CEC from 28.49 meq/100g to 35.51 meq/100g, increase in the SSA from 60.63 m2/g to 104.88 m2/g, significant increase in microporosity which described in the t plots and decrease in the mean particle size distribution peak from 49.28 μm to 38.84 μm. The effect of contact time and effect of adsorbent dosage on Mn sorption was studied. Both unmilled and milled samples reached equilibrium at 24 hours and the pH rose from 4 to 7 in first 30 minutes. The Mn removal percentage increased significantly after milling. Using Langmuir isotherm, the maximum adsorbed metals (qmax) also increased from 0.570 to 4.219 mg/g.

scholarly journals Comparison of Nitrogen Adsorption and Mercury Penetration Results: II. Pore size Distributions Calculated from Type IV Isotherm Data

1988 ◽  
Vol 5 (3) ◽  
pp. 168-190 ◽  
Author(s):  
Bruce D. Adkins ◽  
Burtron H. Davis
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Nitrogen Adsorption ◽  
Type Iv ◽  
Pore Size Distributions ◽  
Nitrogen Desorption ◽  
The Difference ◽  
Penetration Data ◽  
Packed Sphere

The pore distributions calculated from nitrogen desorption and from mercury penetration data are similar for the four materials utilized in this study. While there are small differences in the distributions calculated using different models (Cohan. Foster or Broekhoff-deBoer) with nitrogen adsorption or desorption isotherm data, all three show reasonable agreement with distributions calculated from mercury penetration data. Frequently practical catalysts have such a broad pore size distribution that neither method alone is adequate to measure the total pore size range. The present results suggest a direct comparison, without recourse to a scaling factor, is appropriate when comparing results from the two methods even though the pore size distribution maximum may vary by at least 50% depending upon the model chosen for the calculation. Better agreement may be obtained between the two experimental techniques by adjusting either the nitrogen adsorption data using a packed sphere model or the mercury penetration data by an earlier reported correction ratio. The difference between the two methods becomes less than 20% when a correction procedure is used; however, further studies are needed to define the range of material shaped that these procedures are applicable to.

scholarly journals Impact of Polymer Binders on the Structure of Highly Filled Zirconia Feedstocks

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2247
Author(s):  
Claire Delaroa ◽  
René Fulchiron ◽  
Eric Lintingre ◽  
Zoé Buniazet ◽  
Philippe Cassagnau
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
High Density Polyethylene ◽  
Mercury Porosimetry ◽  
High Density ◽  
Organic Binder ◽  
Molten State ◽  
Homogeneous Dispersion ◽  
The Impact

The impact of polypropylene and high-density polyethylene backbone binders on the structure of organic matrix, feedstock, and ceramic parts is investigated in terms of morphology in this paper. The miscibility of wax with polyethylene and polypropylene is investigated in the molten state via a rheological study, revealing wax full miscibility with high-density polyethylene and restricted miscibility with polypropylene. Mercury porosimetry measurements realized after wax extraction allow the characterization of wax dispersion in both neat organic blends and zirconia filled feedstocks. Miscibility differences in the molten state highly impact wax dispersion in backbone polymers after cooling: wax is preferentially located in polyethylene phase, while it is easily segregated from polypropylene phase, leading to the creation of large cracks during solvent debinding. The use of a polyethylene/polypropylene ratio higher than 70/30 hinders wax segregation and favors its homogeneous dispersion in organic binder. As zirconia is added to organic blends containing polyethylene, polypropylene, and wax, the pore size distribution created by wax extraction is shifted towards smaller pores. Above zirconia percolation at 40 vol%, the pore size distribution becomes sharp attesting of wax homogeneous dispersion. As the PP content in the organic binder decreases from 100% to 0%, the pore size distribution is reduced of 30%, leading to higher densification ability. In order to ensure a maximal densification of the final ceramic, polyethylene/polypropylene ratios with a minimum content of 70% of high-density polyethylene should be employed.

scholarly journals The ALGINATE MICROSPHERES CONTAINING CURCUMIN: PREPARATION, CHARACTERIZATION, AND IN VITRO HUMAN HAEMOGLOBIN GLYCOSYLATION ASSAY

2019 ◽  
pp. 221-225
Author(s):  
KULKARNI AS ◽  
BHUJBAL SS
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Therapeutic Potential ◽  
Release Kinetics ◽  
Glycosylated Hemoglobin ◽  
Scanning Electron Micrographs ◽  
In Vitro Drug Release ◽  
Human Haemoglobin ◽  
Scanning Electron

Objective: The objective of the present study was to formulate, evaluate alginate microspheres of curcumin, and to investigate the inhibitory effect on glycosylated hemoglobin. Methods: All formulations were prepared by an ionotropic gelation technique using sodium alginate as a polymer and calcium chloride as a crosslinker in varying concentrations. The formulation batches (F1–F6) were evaluated for physical properties such as compatibility studies, percentage entrapment efficiency (%EE), microsphere yield, particle size, and polydispersity index. In vitro, drug release was studied and surface morphology was characterized by scanning electron microscopy. Results: The microspheres showed %EE, microsphere yield, particle size in the ranges of 44.86%–84.24%, 43.05%–81.4%, and 352–559 μm, respectively. In vitro, drug release and release kinetics showed that the developed curcumin microspheres system is a promising delivery system for controlled drug release. Scanning electron micrographs indicate porous and rough surface. The inhibitory properties of curcumin and microspheres (F4) on glycosylation formation were investigated in hemoglobin using quercetin as standard. The decreased in hemoglobin concentration after incubation of hemoglobin with a graded concentration of glucose over a specified time was used as an index for in vitro human hemoglobin glycosylation assay. Glycosylation inhibition was about 75% for standard quercetin, 60% for curcumin microspheres, and 38.74% for curcumin suspension occurred after 72 h. Conclusion: From these results, it can be concluded that curcumin in microsphere formulation has better therapeutic potential and could prove to be useful in the development of antidiabetic formulation.

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