Anding Wang

High Bs Fe84−xSi4B8P4Cux (x = 0 – 1.5) nanocrystalline alloys with excellent magnetic softness

The magnetic properties of annealed Fe84−xSi4B8P4Cux (xu2009=u20090, 0.5, 0.75, 1.0, 1.25, 1.5) soft-magnetic alloys prepared by melt–spinning were investigated. In this alloy system, the appropriate addition of the Cu element promotes the precipitation of α-Fe(Si), as well as inhibits the precipitation of other phases. The saturation magnetic flux density Bs increases and the coercivity Hc markedly decreases simultaneously with increasing Cu content until xu2009=u20091.25. The Fe82.75Si4B8P4Cu1.25 alloy annealed at 873 K for 1.8 ks shows a high Bs of 1.83 T and excellent soft-magnetic properties such as a low Hc of 2.1 A/m and a high effect permeability of 31u2009600. It is found that a 1%–1.25% addition of Cu is effective for the improvement of soft-magnetic properties for the present alloy system.

Properties of transparent conducting ZnO : Al oxide thin films and their application for molecular organic light-emitting diodes

ZnO : Al (ZAO) films were deposited on glass substrates by a reactive mid-frequency sputtering system. The microstructural, electrical, and optical properties of ZAO films were investigated. It was observed that the polycrystalline film was (0 0 2n) textured with columnar structure. The minimum resistivity was 1.39×10−4 Ω cm with a carrier concentration of 1.58×1021 cm−3 and a Hall mobility of 28.2 cm2 V−1 s−1, correspondingly with the c-axis nearly equal to the value of ZnO powder and the minimum mechanical stress therein. The average transmittance of 80.8% in the visible range and infrared reflectance of over 86% in the 1600–4400 cm−1 interval were obtained. The ZAO films were used as the transparent anodes to fabricate light-emitting diodes, and a luminance efficiency of 2.09 cd A−1 was measured at a current density of 5.38 A m−2.

Enhancement of glass-forming ability of Fe-based bulk metallic glasses with high saturation magnetic flux density

The effects of substituting Fe with Ni on thermal properties, glass-forming ability (GFA) and magnetic properties of Fe76-xNixMo3.5P10C4B4Si2.5 (x = 0−30 at.%) alloys were investigated in detail. The breadth of the supercooled liquid region was found to gradually increase from 42 to 55 K with increasing Ni content to 30 at.%. When x = 5 at.%, the alloy composition approached a eutectic point, resulting in an increase in GFA. As a result, FeNiMoPCBSi bulk metallic glasses with critical diameters up to 5.5 mm were successfully synthesized by copper mold casting. These glassy alloys exhibit a high saturation magnetic flux density of 0.75−1.21 T and excellent soft magnetic properties, i.e., low coercive force of 1.1−2.0 A/m, and high effective permeability of 14400−19700 at 1 kHz under a field of 1 A/m. The reasons for the high stability of the supercooled liquid, and the high GFA as well as excellent soft magnetic properties are discussed in this article.

Soft magnetic properties of bulk FeCoMoPCBSi glassy core prepared by copper mold casting

Bulk Fe66Co10Mo3.5P10C4B4Si2.5 glassy core of 10 mm in outer diameter, 6 mm in inner diameter, and 1 mm in thickness was successfully prepared by copper mold casting. The effects of annealing treatments on magnetic properties and microstructure of these cores were investigated. After an optimum annealing treatment, the resulting bulk glassy core exhibits good magnetic properties, i.e., high saturation magnetic flux density of 1.23 T, low coercive force of 1.0 A/m, high maximum permeability of 450u2009000, respectively. In addition, the glassy core also shows low core loss of 0.4 W/kg at 50 Hz and at maximum magnetic flux density of 1 T. The synthesis of bulk glassy core with excellent magnetic properties is encouraging for enlarging the application field of ferromagnetic bulk glassy alloys.

Improvement of magnetic properties, microstructure and magnetic structure of Fe73.5Cu1Nb3Si15.5B7 nanocrystalline alloys by two-step annealing process

AbstractFe73.5Cu1Nb3Si15.5B7 nanocrystalline alloys were prepared by using conventional one-step annealing process and two-step annealing process. It was found that two-step annealing process can effectively improve soft magnetic properties and optimize microstructure. By separately controlling the formation of Cu clusters and further optimize the nanocrystalline structure, Bcc α-Fe with the grain size of 13xa0nm is formed in samples pretreated at 400xa0°C and nanocrystallized at 560xa0°C for 1xa0h. The samples exhibit excellent magnetic properties, such as lower coercive force of 0.7xa0A/m, higher initial permeability of 9.16xa0×xa0104, lower core loss of 0.18xa0W/kg at 0.7xa0T and 400xa0Hz, and 0.5xa0W/kg at 0.7xa0T and 1xa0kHz, respectively. The microstructure and magnetic structure evolution during different annealing processes were investigated. Correlation among the magnetic properties, magnetic structures and the microstructures changes in two different crystallization processes was studied systematically.n

Effect of Fe to P concentration ratio on structures, crystallization behavior, and magnetic properties in (Fe0.79+xP0.1-xC0.04B0.04Si0.03)99Cu1 alloys

The effect of Fe to P concentration ratio on structures, crystallization behavior, and magnetic properties in (Fe0.79+xP0.1−xC0.04B0.04Si0.03)99Cu1 alloys was investigated. The increase of Fe to P concentration ratio changes the structure and crystallization process of as-quenched ribbon. Nanocrystalline alloys with excellent soft magnetic properties were synthesized upon annealing the as-quenched ribbon with primary crystals. The (Fe0.84P0.05C0.04B0.04Si0.03)99Cu1 nanocrystalline alloy exhibits excellent magnetic properties, such as high saturation magnetic flux density of 1.74u2009T, low coercivity of 4.9u2009A/m, high effective permeability of 22xa0900 (at 1u2009kHz), low core loss of 3.1u2009W/kg at 1.0u2009T and 400u2009Hz, and 8.9u2009W/kg at 1.0u2009T and 1u2009kHz, respectively.

Two-dimensional simulations of temperature fields of the reactor wall during hot-filament CVD diamond film growth over a large area

In order to study the growth of diamond films over a large area in a traditional hot-filament chemical vapour deposition (HFCVD) reactor, two-dimensional mathematical models were first developed to investigate the temperature fields of the reactor walls, which made significant contributions to thermal round-flow of the reactant gases under different energy transfer systems. The set of partial differential equations involved in the thermal conduction system was solved with different boundary conditions by the finite control volume method. Numerical simulations showed that the temperature space distributions were heterogeneous when thermal radiation was assumed to be the only mechanism in heat transfer from the filaments to the reactor walls. However, taking into account the effects of thermal conduction under adiabatic and different isothermal temperature boundary conditions, the temperature uniformities improved greatly. In addition, thermal convection did not affect the temperature distributions but only increased the total temperature of the reactor wall. These results not only give insight into the dominant reasons resulting in low nucleation density and low growth rate of diamond films, but also provide a basis for the design of industrial HFCVD reactors to obtain high-quality diamond films over a large area.