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Full-Text Articles in Engineering

Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. Shield, D. Heiman, L. Lewis Aug 2013

Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. Shield, D. Heiman, L. Lewis

Donald Heiman

Effects of nanostructuring on the magnetostructural response of the near-equiatomic FeRh phase were investigated in nanocomposite materials synthesized by rapid solidification and subsequent annealing of an alloy of nominal atomic composition (FeRh)5Cu95. Transmission electron microscopy studies confirm attainment of a phase-separated system of nanoscaled (∼10–15 nm diameter) precipitates, consistent with FeRh embedded in a Cu matrix. These nanoprecipitates are crystallographically aligned with the coarse-grained Cu matrix and possess an L10-type (CuAu 1) structure, in contrast to the B2 (CsCl)-type structure of bulk FeRh. It is proposed that the face-centered cubic crystal structure of the …


Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris Aug 2013

Direct Chemical Synthesis Of High Coercivity Air-Stable Smco Nanoblades, C. N. Chinnasamy, J. Y. Huang, L. H. Lewis, B. Latha, C. Vittoria, V. G. Harris

Laura H. Lewis

Ferromagnetic air-stable SmCo nanoparticles have been produced directly using a one-step chemical synthesis method. X-ray diffraction studies confirmed the formation of hexagonal SmCo5 as a dominant phase. High resolution transmission electron microscopy confirms the presence of uniform, anisotropic bladelike nanoparticles approximately 10 nm in width and 100 nm in length. Values of the intrinsic coercivity and the magnetization in the as-synthesized particles are 6.1 kOe and 40 emu/g at room temperature and 8.5 kOe and 44 emu/g at 10 K, respectively. This direct synthesis process is environmentally friendly and is readily scalable to large volume synthesis to meet the needs …


Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis Aug 2013

Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis

Laura H. Lewis

Effects of nanostructuring on the magnetostructural response of the near-equiatomic FeRh phase were investigated in nanocomposite materials synthesized by rapid solidification and subsequent annealing of an alloy of nominal atomic composition (FeRh)5Cu95. Transmission electron microscopy studies confirm attainment of a phase-separated system of nanoscaled (∼10–15 nm diameter) precipitates, consistent with FeRh embedded in a Cu matrix. These nanoprecipitates are crystallographically aligned with the coarse-grained Cu matrix and possess an L10-type (CuAu 1) structure, in contrast to the B2 (CsCl)-type structure of bulk FeRh. It is proposed that the face-centered cubic crystal structure of the Cu matrix serves as a template …


Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis Jul 2013

Tuning The Magnetostructural Phase Transition In Ferh Nanocomposites, Radhika Barua, Xiujuan Jiang, Felix Jiménez-Villacorta, J. E. Shield, D. Heiman, L. H. Lewis

Felix Jiménez-Villacorta

Effects of nanostructuring on the magnetostructural response of the near-equiatomic FeRh phase were investigated in nanocomposite materials synthesized by rapid solidification and subsequent annealing of an alloy of nominal atomic composition (FeRh)5Cu95. Transmission electron microscopy studies confirm attainment of a phase-separated system of nanoscaled (∼10–15 nm diameter) precipitates, consistent with FeRh embedded in a Cu matrix. These nanoprecipitates are crystallographically aligned with the coarse-grained Cu matrix and possess an L10-type (CuAu 1) structure, in contrast to the B2 (CsCl)-type structure of bulk FeRh. It is proposed that the face-centered cubic crystal structure of the Cu matrix serves as a template …


Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou Jul 2013

Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou

Jianli Wang

A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K and an adiabatic temperature change …


Fabrication, Magnetic, And Ferroelectric Properties Of Multiferroic Bifeo3 Hollow Nanoparticles, Yi Du, Zhenxiang Cheng, S X. Dou, Darren J. Attard, Xiaolin Wang Jun 2013

Fabrication, Magnetic, And Ferroelectric Properties Of Multiferroic Bifeo3 Hollow Nanoparticles, Yi Du, Zhenxiang Cheng, S X. Dou, Darren J. Attard, Xiaolin Wang

Shi Xue Dou

Hollow BiFeO3 nanoparticles were synthesized by an electrospray route for the first time. The phase purity and structure have been investigated by x-ray diffraction and Raman spectroscopy. Transmission and scanning electron microscope investigations revealed that the as-obtained BiFeO3 hollow spheres were polycrystalline, with a shell thickness of 35 nm. The formation mechanism can be possibly explained by Ostwald ripening. Raman spectra have verified decreased vibrational frequencies in BiFeO3 nanoparticles. These hollow and core-shell multiferroic nanoparticles exhibit significantly enhanced ferromagnetism from 5 to 600 K due to a broken spiral spin structure. The ferroelectricity of hollow BiFeO3 particles exhibits a lower …


Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou Jun 2013

Abnormal Magnetic Behaviors And Large Magnetocaloric Effect In Mnps3 Nanoparticles, R Zeng, S Q. Wang, G D. Du, Jianli Wang, J C. Debnath, Precious Shamba, Z Y. Fang, S. X. Dou

Shi Xue Dou

A nanostructured honeycomb lattice consisting of MnPS3 nanoparticles synthesized via the ion-exchange technique was found to have restacked molecular layers stabilized by H2O insertion between the layers. Susceptibility (χ) and heat capacity measurements showed the absence of long range magnetic ordering, at least down to 2 K. However, the χ data showed that the system possesses a high effective Curie temperature, suggesting that the system is in a high spin lattice disordered state. Evaluation of the magnetocaloric effect indicates that the system has a large reversible magnetic-entropy change (−ΔSm) of 6.8 and 12.8 J/kg K and an adiabatic temperature change …


Magnetic And Ferroelectric Properties Of Multiferroic Bi2nimno6 Nanoparticles, Yi Du, Zhenxiang Cheng, Xiaolin Wang, Peng Liu, S. X. Dou Jun 2013

Magnetic And Ferroelectric Properties Of Multiferroic Bi2nimno6 Nanoparticles, Yi Du, Zhenxiang Cheng, Xiaolin Wang, Peng Liu, S. X. Dou

Shi Xue Dou

Multiferroic Bi2NiMnO6 nanoparticles were synthesized by a simple electrospray method. Bi2NiMnO6 nanoparticles crystallize in the monoclinic structure with space group C121. The particles show a uniform spherical shape with a diameter of 100 nm to 300 nm. The ferromagnetic transition of Bi2NiMnO6 is confirmed at 122 K. The room temperature ferroelectricity of the Bi2NiMnO6 nanoparticles is verified by Kelvin probe force microscopy.


Influence Of Ni Nanoparticle On The Morphology And Growth Of Interfacial Intermetallic Compounds Between Sn-3.8ag-0.7cu Lead-Free Solder And Copper Substrate Feb 2013

Influence Of Ni Nanoparticle On The Morphology And Growth Of Interfacial Intermetallic Compounds Between Sn-3.8ag-0.7cu Lead-Free Solder And Copper Substrate

A.S. Md Abdul Haseeb

This paper reports on the effects of adding Ni nanoparticles to a Sn-3.8Ag-0.7Cu solder. The nanocomposite was prepared by manual blending of SAC solder paste with various percentages of Ni particles. Results showed that the addition of Ni nanoparticles did not bring any significant change in the onset melting temperature of the solder. An increase in the weight percentage of nanoparticles in the solder caused an increase of the wetting angle and a decrease of spreading rate. Moreover, the addition of Ni nanoparticles changed the interfacial intermetallic compound morphology from a scalloped structure into a planar type structure, enhanced the …


Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate Jan 2013

Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to investigate the effects of zinc (Zn) nanoparticles on the interfacial intermetallic compounds (IMCs) between Sn-3.8Ag-0.7Cu (SAC) solder and Cu substrate during multiple reflow. Design/methodology/approach - The nanocomposite solders were prepared by manually mixing of SAC solder paste with varying amounts of Zn nanoparticles. The solder pastes were reflowed on a hotplate at 250 C for 45 s for up to six times. The actual Zn content after reflow was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The wetting behavior of the solders was characterized by analyzing the contact angles and …


Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate Jan 2013

Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to investigate the effects of zinc (Zn) nanoparticles on the interfacial intermetallic compounds (IMCs) between Sn-3.8Ag-0.7Cu (SAC) solder and Cu substrate during multiple reflow. Design/methodology/approach - The nanocomposite solders were prepared by manually mixing of SAC solder paste with varying amounts of Zn nanoparticles. The solder pastes were reflowed on a hotplate at 250 C for 45 s for up to six times. The actual Zn content after reflow was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The wetting behavior of the solders was characterized by analyzing the contact angles and …


Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate Jan 2013

Effects Of Reflow On The Interfacial Characteristics Between Zn Nanoparticles Containing Sn-3.8ag-0.7cu Solder And Copper Substrate

A.S. Md Abdul Haseeb

Purpose - The purpose of this paper is to investigate the effects of zinc (Zn) nanoparticles on the interfacial intermetallic compounds (IMCs) between Sn-3.8Ag-0.7Cu (SAC) solder and Cu substrate during multiple reflow. Design/methodology/approach - The nanocomposite solders were prepared by manually mixing of SAC solder paste with varying amounts of Zn nanoparticles. The solder pastes were reflowed on a hotplate at 250 C for 45 s for up to six times. The actual Zn content after reflow was analyzed by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The wetting behavior of the solders was characterized by analyzing the contact angles and …


Tem Analysis As A Tooll For Toxicology Assessment Of Occupational Exposure To Airborne Nanoparticles From Welding, João F. Gomes Jan 2013

Tem Analysis As A Tooll For Toxicology Assessment Of Occupational Exposure To Airborne Nanoparticles From Welding, João F. Gomes

João F Gomes

No abstract provided.


Notice On A Methodology For Characterizing Emissions Of Ultrafine Particles/Nanoparticles In Microenvironments, João F. Gomes Jan 2013

Notice On A Methodology For Characterizing Emissions Of Ultrafine Particles/Nanoparticles In Microenvironments, João F. Gomes

João F Gomes

No abstract provided.