scholarly journals Application of Silica–Coated Magnetite on a Steel Plate and its Frictional and Thermal Effect

2020 ◽  
Vol 65 (1) ◽  
pp. 76-85
Author(s):  
Indri Dayana ◽  
Anggito P. Tetuko ◽  
Timbangen Sembiring ◽  
Kurnia Sembiring ◽  
Nining S. Asri ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Steel Plate ◽  
Average Particle Size ◽  
Optical Microscope ◽  
Average Particle ◽  
Friction Process ◽  
Magnetite Fe3o4 ◽  
Promising Application ◽  
Magnetite Particles ◽  
Dsc Curves

The magnetite (Fe3O4) particles that have been coated using tetraethyl orthosilicate (TEOS) as silica precursors were used as the additive in the lubricant. The effects of silica-coated magnetite additive on the thermal properties of ferro-lubricant and reducing the friction on a steel plate have been investigated. The characterizations were conducted at both conditions: with and without the addition of Fe3O4 particles. The characterization using TEM proposed that the average particle size of the silica-coated magnetite particles is 150 nm. The TGA/DSC curves of the silica-coated magnetite particles suggested a gradual weight loss obtained as the temperature increased. The endothermic peak was obtained at ~37 and 50 °C. The silica-coated magnetite particles’ additive increases both the density and viscosity of 0.84 g/cm3 and 134.29 cSt. The silica-coated magnetite particles additive in the lubricant enhances the thermal conductivity and specific heat of 0.151 W/m.K and 1600 J/kg.K. Ferro-lubricant reduces the friction coefficient up to 0.02 (static) and 0.005 (dynamic). The wear resistance of the plate could be improved as analyzed using an optical microscope. These results demonstrate a promising application of the silica-coated magnetite particles as an additive in the lubricant. Therefore improving wear resistance and cooling during the friction process.

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

scholarly journals Effect of the polymeric coating over Fe3O4 particles used for magnetic separation

2010 ◽  
Vol 8 (5) ◽  
pp. 1041-1046 ◽  
Author(s):  
Raúl Reza ◽  
Carlos Martínez Pérez ◽  
Claudia Rodríguez González ◽  
Humberto Romero ◽  
Perla García Casillas
Keyword(s):  
Particle Size ◽  
Magnetite Nanoparticles ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Polymeric Coating ◽  
Average Particle ◽  
Synthesis Conditions ◽  
Aging Conditions ◽  
Magnetite Particles ◽  
Average Size

AbstractIn this work, the synthesis of magnetite nanoparticles by two variant chemical coprecipitation methods that involve reflux and aging conditions was investigated. The influence of the synthesis conditions on particle size, morphology, magnetic properties and protein adsorption were studied. The synthesized magnetite nanoparticles showed a spherical shape with an average particle size directly influenced by the synthesis technique. Particles of average size 27 nm and 200 nm were obtained. When the coprecipitation method was used without reflux and aging, the smallest particles were obtained. Magnetite nanoparticles obtained from both methods exhibited a superparamagnetic behavior and their saturation magnetization was particle size dependent. Values of 67 and 78 emu g−1 were obtained for the 27 nm and 200 nm magnetite particles, respectively. The nanoparticles were coated with silica, aminosilane, and silica-aminosilane shell. The influence of the coating on protein absorption was studied using Bovine Serum Albumin (BSA) protein.

PREPARATION OF NANO-TATB BY SEMIBATCH REACTION CRYSTALLIZATION

NANO ◽  
2013 ◽  
Vol 08 (05) ◽  
pp. 1350055 ◽  
Author(s):  
XUE-RONG TAN ◽  
XIAO-HUI DUAN ◽  
CHONG-HUA PEI ◽  
HONG-LIN XU
Keyword(s):  
Grain Size ◽  
Average Particle Size ◽  
Reaction System ◽  
Xrd Analysis ◽  
Differential Scanning Calorimetric ◽  
Average Particle ◽  
Bet Method ◽  
Close Relationship ◽  
Dsc Curves ◽  
Semibatch Reaction

The 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) nanoparticles were prepared by using semibatch reaction crystallization method, and the influencing factors in close relationship with the grain size and crystal morphology control, such as the concentration of reaction system and categories of surfactants, were studied in this paper. The synthesized nano-TATB particles had been characterized by SEM, XRD, thermo gravimetric/differential scanning calorimetric (TG/DSC) and N 2 physisorption. The grain size of TATB particles using nonionic surfactant as the additive ranged from 30 nm to 65 nm with a shape of spheres or ellipsoids. The broadening of the peaks and the weakening of the strength for nano-TATB were observed by XRD analysis. The corrected average particle size of nano-TATB was calculated using the Debye–Scherrer equation and the range was from 18 nm to 50 nm. TG and DSC curves revealed that thermal decomposition of nano-TATB occurred in the range of 361.5°C–385.0°C and its peak temperature was 373.7°C with a decrease of approximately 7°C compared with original TATB. Furthermore, the specific surface area (21.54 m2/g) of nano-TATB was calculated by BET method using N 2 physisorption (at 77°C).

Microwave Properties of Polymer Composites Containing Combinations of Micro- and Nano-Sized Magnetic Fillers

2008 ◽  
Vol 8 (2) ◽  
pp. 650-654 ◽  
Author(s):  
Svetoslav Kolev ◽  
Tatyana Koutzarova ◽  
Andrey Yanev ◽  
Chavdar Ghelev ◽  
Ivan Nedkov
Keyword(s):  
Magnetic Material ◽  
Magnetocrystalline Anisotropy ◽  
Average Particle Size ◽  
Anisotropy Field ◽  
Anisotropy Constant ◽  
Strontium Hexaferrite ◽  
Filler Concentration ◽  
Average Particle ◽  
Effective Anisotropy ◽  
Magnetite Particles

We investigated the microwave absorbing properties of composite bulk samples with nanostructured and micron-sized fillers. As magnetic fillers we used magnetite powder (Fe3O4 with low magnetocrystalline anisotropy) and strontium hexaferrite (SrFe12O19 with high magnetocrystalline anisotropy). The dielectric matrix consisted of silicone rubber. The average particle size was 30 nm for the magnetite powder and 6 μm for the strontium hexaferrite powder. The micron-sized SrFe12O19 powder was prepared using a solid-state reaction. We investigated the influence of the filler concentration and the filler ratio (Fe3O4/SrFe12O19) in the polymer matrix on the microwave absorption in a large frequency range (1 ÷ 18 GHz). The results obtained showed that the highly anisotropic particles become centers of clusterification and the small magnetite particles form magnetic balls with different diameter depending on the concentration. The effect of adding micron-sized SrFe12O19 to the nanosized Fe3O4 filler in composites absorbing structures has to do with the ferromagnetic resonance (FMR) shifting to the higher frequencies due to the changes in the ferrite filler's properties induced by the presence of a magnetic material with high magnetocrystalline anisotropy. The two-component filler possesses new values of the saturation magnetization and of the anisotropy constant, differing from those of both SrFe12O19 and Fe3O4, which leads to a rise in the effective anisotropy field. The results demonstrate the possibility to vary the composite's absorption characteristics in a controlled manner by way of introducing a second magnetic material.

Preparation of Polymer Microspheres Using Silane Coupling Agent Modified Nano-SiO2 as Single Stabilizer

2011 ◽  
Vol 341-342 ◽  
pp. 247-251 ◽  
Author(s):  
Guang Hui Ma ◽  
Fa Ai Zhang ◽  
Chang Sheng Gu
Keyword(s):  
Silica Nanoparticles ◽  
Average Particle Size ◽  
Optical Microscope ◽  
Coupling Agents ◽  
Average Particle ◽  
Silane Coupling Agents ◽  
Pickering Emulsion Polymerization ◽  
Silane Coupling ◽  
Unmodified Silica

This paper demonstrates that silica nanoparticles were modified by the four silane coupling agents (KH-151, KH-550, KH-560, KH-570) firstly, then polystyrene/silica (PS/SiO2) composite microsphere with PS core and silica nanoparticles shell were prepared by Pickering emulsion polymerization. The characterization of optical microscope (OM), scanning electron microscope (SEM), and thermogravimetic analysis ( TGA) illustrates that these microsphere are composed of PS and silica nanoparticles. Silica nanoparticles modified by the different silane coupling agents could form the stable PS/SiO2 microsphere over 70 °C, while the unmodified silica nanoparticles are difficult to form stable PS/SiO2 microspheres at the same temperature. The PS/KH-151-SiO2 microsphere exhibits the least average particle size, while the PS/KH-570-SiO2 microsphere produces the largest. Both SEM and TGA confirm that microsphere surface exists solid nanoparticles.

scholarly journals Structural and Magnetic Properties of Ni/C Composites Synthesized from Beet Pulp and Corn Stems

2021 ◽  
Vol 7 (3) ◽  
pp. 31
Author(s):  
Ihor Bordun ◽  
Anna Pidluzhna ◽  
Fedir Ivashchyshyn ◽  
Anatoliy Borysiuk ◽  
Dariusz Całus ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Raw Materials ◽  
Average Particle Size ◽  
Carbon Composites ◽  
Activation Technique ◽  
Average Particle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Beet Pulp ◽  
Promising Application

Nickel/carbon composites were synthesized by the carbonization method with the use of the steam-gas activation technique. Beet pulp and corn stems were used as initial raw materials for composites synthesis. The obtained substances were analyzed by means of scanning electron microscopy, X-ray diffraction analysis, and magnetic properties investigation. The presence of nickel in synthesized composites was estimated during analysis, and the average particle size of nickel was determined as well. The specific surface area of the obtained samples was measured by the technique of Methylene blue sorption from the aqueous solution. The results of the performed investigation demonstrate clearly the promising application of synthesized composites as magneto-active sorbents, which could be easily separated from water solutions.

scholarly journals Low-Temperature Adsorption Study of Carbon Dioxide on Porous Magnetite Nanospheres Iron Oxide

2021 ◽  
Vol 12 (5) ◽  
pp. 6252-6268
Keyword(s):  
Adsorption Isotherms ◽  
High Efficiency ◽  
Co2 Adsorption ◽  
Average Particle Size ◽  
Total Pore Volume ◽  
Spherical Shape ◽  
Bet Surface Area ◽  
Average Particle ◽  
Type I ◽  
Magnetite Fe3o4

Porous magnetite Fe3O4 nano-spheres (PMNs) have been successfully produced and have been demonstrated to be high-efficiency adsorbents. The PMNs have a spherical shape with an average particle size of 25.84 nm. The BET surface area of PMNs is 143.65 m2g-1, with a total pore volume of 0.16 cm3g-1. As a result of CO2 adsorption and desorption features on dry PMNs, this synthesized material is projected to be exploited as possible CO2 sequestration reservoirs to minimize greenhouse gas emissions. CO2 adsorption was best at low temperatures and with dry PMNs. PMNs, on the other hand, has a very high adsorption capacity of 0.96 mmol/g. According to the IUPAC categorization of adsorption isotherms, all CO2 adsorption isotherms of coal samples fall into type I, which most likely indicates adsorption restricted to a few layers of molecules (micropores and mesopores). Langmuir, Henry, Dubbin, Temkin, Toth, Harkin-Jura, Elovich, Redlich Peterson, and Josene models suit any experimental adsorption data that best predict the heterogeneous surface features of PMNs.

Tribological Characteristics Manufactures SiC by Liquid Phase Sintered Method

2006 ◽  
Vol 324-325 ◽  
pp. 1177-1180
Author(s):  
Won Jo Park ◽  
Sun Chul Huh ◽  
Sung Ho Park ◽  
Hong Tae Song
Keyword(s):  
Wear Resistance ◽  
Liquid Phase ◽  
Coefficient Of Thermal Expansion ◽  
Average Particle Size ◽  
High Temperature Strength ◽  
Average Particle ◽  
Pressing Method ◽  
Sintering Additives ◽  
Resistance To Oxidation ◽  
Sic Composites

SiC materials have excellent high temperature strength, low coefficient of thermal expansion, good resistance to oxidation and good thermal and chemical stability etc. In this study, monolithic liquid phase sintered SiC (LPS-SiC) was made by hot pressing method with nano-SiC powder an average particle size is 30nm and less. Alumina (Al2O3), yttria (Y2O3) and silica (SiO2) particles were used for sintering additives. To investigate effects of SiO2, Al2O3/Y2O3 composition was fixed and then ratios of SiO2 were changed as seven kinds. Materials have been sintered for 1 hour at 1760, 1780 and 1800 under the pressure of 20MPa. The system of sintering additives which affects a property of sintering as well as the influence depending on compositions of sintering additives were investigated by measurement of density, mechanical properties such as Vickers hardness and sliding wear resistance were investigated to make sure of the optimum condition which is about matrix of SiCf/SiC composites. The abrasion test condition applies to load of 20N at 100rpm for 20min. Sintered density, abrasion property of fabricated LPS-SiC increased with increasing the sintering temperature. In case of LPS-SiC with low SiO2 content, has very excellent wear resistance.

scholarly journals Hydroxyapatite-Based Magnetic Bionanocomposite as Pharmaceuticals Carriers in Chitosan Scaffolds

2021 ◽  
Vol 5 (2) ◽  
pp. 37
Author(s):  
Anderson Valério Chaves ◽  
Rafael Melo Freire ◽  
Victor Pinheiro Feitosa ◽  
Nágila Maria Pontes Silva Ricardo ◽  
Juliano Casagrande Denardin ◽  
...  
Keyword(s):  
Bone Growth ◽  
Average Particle Size ◽  
Electronic Spectroscopy ◽  
Average Particle ◽  
High Porosity ◽  
Magnetite Fe3o4 ◽  
Freeze Dried ◽  
Chitosan Scaffolds ◽  
Co Precipitation ◽  
New System

Hydroxyapatite (HA) is a bioceramic very similar to the mineral component of bones and teeth. It is well established that osteoblasts grow better onto HA-coated metals than on metals alone. Herein, the preparation of a new system consisting of magnetite (Fe3O4) and HA functionalized with oleic acid and simvastatin (SIMV), and incorporated in chitosan (CHI) scaffolds, was undertaken. HA was synthesized by the hydrothermal method, while Fe3O4 was synthesized by co-precipitation. The polymer matrix was obtained using a 2% CHI solution, and allowed to stir for 2 h. The final material was freeze-dried to produce scaffolds. The magnetic properties remained unchanged after the formation of the composite, as well as after the preparation of the scaffolds, maintaining the superparamagnetism. CHI scaffolds were analyzed by scanning electronic spectroscopy (SEM) and showed a high porosity, with very evident cavities, which provides the functionality of bone growth support during the remineralization process in possible regions affected by bone tissue losses. The synthesized composite showed an average particle size between 15 and 23 nm for particles (HA and Fe3O4). The scaffolds showed considerable porosity, which is important for the performance of various functions of the tissue structure. Moreover, the addition of simvastatin in the system can promote bone formation.

Preparation and Properties of Magnesium-Aluminum Matrix Composites Reinforced with Silicon Carbon Particles

2012 ◽  
Vol 583 ◽  
pp. 3-8 ◽  
Author(s):  
Tan Wei Zhou ◽  
Xiang Rong Liu ◽  
Run Lan Zhang ◽  
Zhuang Zhuang Su
Keyword(s):  
Average Particle Size ◽  
Aluminum Matrix ◽  
Optical Microscope ◽  
Aluminum Matrix Composites ◽  
Al Alloy ◽  
Average Particle ◽  
Carbon Particles ◽  
Sic Particles ◽  
Silicon Carbon ◽  
The Matrix

Mg-5wt.%Al alloy based composites reinforced with 0wt.%, 1wt.%, 2wt.% silicon carbon (SiC) particles (average particle size about 3.5µm) were prepared under flux protection conditions. The microstructures, textures, components and hardness of the above composites were investigated through optical microscope, scanning electron microscope, X-ray diffraction and sclerometer. The results indicate that SiC particles are distributed along grain boundaries, limiting grain growth and conducing to the refinement of the matrix. The hardness of composites increases with the increase of SiC particles addition amount. The presences of Mg2Si and the binary carbide Al4C3 were observed in the composites. The Al4C3 phase has a crystal structure closer to that of Mg than to that of SiC, which can be act as a potential nucleant for Mg-5wt.%Al alloy.

Sign in / Sign up

Export Citation Format

Share Document