Materials Literature
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We have investigated the sensitivity of structural, magnetic, and magnetocaloric properties of (Hf0.83Ta0.17)Fe2+x alloys (x=−0.18, −0.09, −0.02, 0.00, 0.09, 0.26) to Fe content. As-cast samples for all x consist essentially exclusively of hexagonal MgZn2-type material. Via magnetization and differential scanning calo…
Sulfone-containing polyesters of 18 kinds having inherent viscosities of 1.19–0.16 dL g−1 were prepared derived from 4,4′-sulfonyl dibenzoyl chloride by solution polycondensation from various aromatic and aliphatic diols in nitrobenzene at 82°C. The polyesters were examined with IR spectra, inherent viscosity, x-ray d…
Low pressure inductively coupled plasma enhanced chemical vapor deposition (ICP–CVD) made it possible to deposit stoichiometric boron nitride (BN) films with thickness gradients in lateral direction, which clearly demonstrate the progresses of the cubic BN (c-BN) growth. Under optimal deposition conditions, single-pha…
The results of an extended investigation of the monoclinic (M2)–monoclinic (M3) phase transition in the mixed AgNbxTa1−xO3 system (ATN) with high concentration of niobium (Nb) are presented in this paper. ATN’s dielectric properties make it promising for microwave technologies and stimulate investigations of the niobi…
The process of bias enhanced nucleation of microwave chemical vapor deposited diamond on silicon has been extensively characterized using plasma diagnostics, scanning and transmission electron microscopy (TEM), Raman spectroscopy, and x-ray diffraction. The nucleation kinetics were measured as a function of bias volta…
An investigation was conducted comparing the corrosion behavior of NdFeB magnets in flowing hydrogen and in the heat and humidity of an autoclave. The results show that corrosion is both macroscopically and microscopically similar in both environments. In both cases, the corrosion progressed most rapidly in those area…
We report that a Au/Ge/Pd layered structure can result in low contact resistivities (∼10−6 Ω cm2) to n-GaAs processed in three temperature ranges (175–200, 340–350, and 425–450 °C). The contacts processed below the Au–Ge eutectic temperature (361 °C) show good surface and interface morphology, thermal stability, Au wi…
Magnets with a nominal composition of Nd14.5Fe79.5B6 have been prepared by the conventional powder metallurgy technique. Precursor alloy powders with average particle sizes of 2.5, 3.0, 3.5, and 4.2 μm were included in this study. Average particle size and oxygen content were effectively manipulated to control the ave…
Direct current hysteresis loops of 49%Co–2%V–Fe alloy have been measured at temperatures up to 800 °C. Two phase structure is evident in the B–H loops between 580 and 730 °C. This alloy cannot be reliably operated above 580 °C. The second magnetic phase is believed to result from the nucleation and growth of disordere…
The result of spin-polarized band calculation for Fe16N2 is presented. The most distant Fe atoms from N is found to have the largest magnetic moment. The major role of the N atom is to expand the Fe lattice, leading to the enhancement of the magnetic moments. Quantitatively speaking, the calculated moment of Fe16N2 is…
Experimental inelastic electron-scattering cross sections of Si and Fe determined from reflection-electron-energy-loss spectroscopy (REELS) experiments are presented. Three primary energies of the electrons (300, 800, and 2000 eV) and three experimental geometries have been considered. The cross sections have been com…
Ni–Co ferrite has been studied with Mössbauer spectroscopy and x-ray diffraction. The crystal structure for this system is spinel, and the lattice constant is in accord with Vegard’s law. The Mössbauer spectra consist of two six-line patterns corresponding to Fe3+ at the tetrahedral (A) and octahedral (B) sites. The N…
A thin electromagnetic wave absorber has been investigated; it is composed of hexagonal ferrite and retains high permeability even in the gigahertz-range. The grid-type wave absorber composed of the hexagonal ferrite was examined to broaden the bandwidth in a gigahertz-range by introducing free space in the direction…
Anisotropic Nd–Fe–B magnet powders can be produced by the hydrogenationdecomposition-desorption-recombination (HDDR) process from Nd–Fe–B–Co–M (M=Ga, Zr, Nb, Hf, and Ta) alloys. The present status of those HDDR powders and the bonded magnets made from them are reviewed with regards to the powder particle size dependen…
The microstructure and electrical properties of tin-doped indium oxide thin films crystallized under the action of a temperature gradient are compared with those of films prepared under uniform temperature. This zone-confining process, coupled with slow deposition rates, causes preferential segregation of dopants from…
The dissolution mechanism of rubbery polymers was analyzed by dividing the penetrant concentration field into three regimes that delineate three distinctly different transport processes. The solvent penetration into the rubbery polymer was assumed to be Fickian. The mode of mobility of the polymer chains was shown to…
Field emission of electrons from boron- and nitrogen-doped diamond is compared. Emission from boron-doped diamond requires vacuum electric fields of 20–50 V μm−1, while nitrogen-doped, type Ib diamond requires fields of 0–1 V μm−1. Since boron-doped diamond is very conductive, very little voltage drop occurs in the di…
Modifications of the magnetic properties of a nonoriented 3% SiFe alloy with plastic strains are reported. The samples have been tested along rolling and transverse directions lying in the sheet plane by means of a suitable experimental system of measurements using a 50 Hz sinusoidal magnetic field. The magnetic prope…
Optical absorption curves for nominally pure and Ce 3+ doped single crystals of Y 3 Al 5 O 12 (YAG) have been measured in the region of 5 eV–7 eV at 292 K, 78 K and 10 K. The parameters of the Urbach rule have been determined referring to those optical absorption curves which are believed to be the fundamental absorpt…
The Jiles–Atherton theory is based on considerations of the dependence of energy dissipation within a magnetic material resulting from changes in its magnetization. The algorithm based on the theory yields five computed model parameters, MS, a, α, k, and c, which represent the saturation magnetization, the effective d…