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1.
Applying the hypercooling technique, the metastable-phase Fe3B, instead of the stable-phase Fe2B, is formed directly in the bulk Fe-B eutectic alloy melt and can be further preserved at room temperature. Measurement of magnetic properties shows that, for the bulk Fe-B eutectic alloy with Fe3B phase, the intrinsic coercivity and retentivity become smaller, and the saturation magnetization is larger, than the stable eutectic alloy (α-Fe/Fe2B) and some Fe-B amorphous alloys.  相似文献   

2.
刘应开  侯德东  周效锋  刘佐权 《物理学报》1999,48(12):2304-2307
研究激波对非晶FeBSi,FeMoBSi合金的影响,经X射线衍射分析,测定主晶化相α-Fe(Mo,B,Si)晶格常量.结果表明:晶格常量比正常值偏小,用双势模型计算晶格常量,理论值与实验符合得很好.从而肯定晶格常量变小是形成B的替代式固溶体和缺位式固溶体所致. 关键词:  相似文献   

3.
张延忠 《物理学报》1985,34(11):1377-1384
在0—300℃范围内考查了非晶Fe82Si5B13合金的磁导率等温弛豫动力学行为,给出了等时弛豫谱,观察到四个弛豫峰。测量表明,总的磁导率弛豫由两种弛豫过程组成,即对于退磁可逆的普通减落和对于退磁不可逆的磁导率连续衰减。计算了弛豫时间和激活能的分布,表明弛豫时间和激活能有宽的分布。普通减落和磁导率衰减过程的最可几激活能分别为1.0eV和1.4eV。对退火的样品,观察到磁导率先是增大而后是衰减的广义cross-over效应。 关键词:  相似文献   

4.
王文魁  王松涛  陈红  何寿安 《物理学报》1984,33(10):1448-1453
研究高压对非晶Fe82Si4B14合金晶化过程的影响,给出常压下与77kbar下的时间-温度-变态图(即T-T-T图)。结果表明:合金晶化温度的压力梯度值随晶化进行的时间长短而改变。常压下晶化时,bcc-Fe(Si)固溶体相先形成;77kbar下晶化时,DOe型Fe3B与bcc-Fe(Si)固溶体相同时出现。 关键词:  相似文献   

5.
Though much progress has been made on the phase transformation kinetics model, little attention has been paid to the incubation reaction before the transformation initiates. In this study, the kinetics characteristics of the incubation time during isothermal reaction and the onset temperature during isochronal one are indicated. A model is established with the consideration of the incubation time corresponding to its annealing temperature during the isothermal case and the onset temperature corresponding to its heating rate during the isochronal case, from which a correlation between the incubation time and the onset temperature can be drawn. Finally, the proposed model has been applied well to the crystallization of Mg65Cu25Y10 amorphous alloy.  相似文献   

6.
纳米微晶Fe69.5(CuCrV)9.5Si13B8超铁磁性研究   总被引:1,自引:0,他引:1       下载免费PDF全文
经813K温度退火后的纳米微晶Fe_(?)(CuCrV)_(9.5)Si_(13)B_8由α-Fe(Si)晶粒和晶界两种磁相组成,温度从10—8l3K的穆斯堡尔研究显示晶粒的超精细场随着温度的变化曲线上有一个转折.用超铁磁性模型进行拟合,结果表明晶界和晶粒间存在强的交换耦合作用,使晶粒的有效磁各向异性常数减小为原来的六分之一. 关键词:  相似文献   

7.
徐祖雄  马如璋 《物理学报》1988,37(11):1843-1848
用穆斯堡尔谱和X射线衍射方法,研究了急冷非晶态合金薄带Fe81B13.5Si3.5C2在空气中退火时磁各向异性的变化,及其与表面结晶和整体结晶的相关性。实验表明,在空气中退火时,磁各向异性的反常变化亦与表面结晶向体结晶的发展密切相关。 关键词:  相似文献   

8.
SmCo5/α-Fe nanocomposite magnets with different morphology have been fabricated by ball milling of the micrometer sized SmCo5 and α-Fe powders. The α-Fe grains vary from elongated nano-strips to spherical nanoparticles with increasing milling time. The inter-phase exchange coupling is enhanced with increasing milling time due to reduced grain size. The first-order reversal curves (FORCs) are taken to identify optimal conditions for exchange coupling. It has been found that the stripped morphology results in weak inter-phase exchange coupling, while enhanced exchange coupling is observed with further reduction of the soft-phase grain size. Compared with the measurement of demagnetization curves, FORC analysis provides more information on the magnetostatic as well as the exchange interactions.  相似文献   

9.
非晶合金Fe78Si9B13在脉冲电流作用下的单相晶化   总被引:3,自引:0,他引:3       下载免费PDF全文
对非晶合金Fe78Si9B13进行了超短脉冲电流处理,实现了晶化时α-Fe(Si)单相结构析出.可以认为,脉冲电流作用时,电子运动与非晶中空位型结构缺陷间的周期性排斥效应促进了类金属原子从非晶结构单元中析出,使Fe(Si)原子局部富集,导致基体金属相在较低温度下优先成核.而在空位的定向迁移的同时,将伴随B原子的扩散,则B原子局域富集,Fe-B化合物的形核析出就要受到这两个因素的抑制 关键词:  相似文献   

10.
采用水雾化方法制备Fe74Al4Sn2P10C2B4Si4合金粉末,研究发现该合金具有强的非晶形成能力和高热稳定性,在粉末粒度小于400目时可以形成非晶态合金.采用该非晶粉末制备的磁粉芯在高频下品质因数显著高于MPP粉芯,说明该磁粉芯高频损耗较低.分析表明,非晶合金磁粉芯高频下损耗低的主要原因是电阻率较高. 关键词: 非晶合金 磁粉芯 玻璃形成能力 软磁性能  相似文献   

11.
12.
The FTIR spectrum of pentafluoroethane (R125) was measured in the mid infrared region from 900 to 4000 cm−1. Vibrational assignments for R125 are revised by comparison of previous and current experimental data with ab initio calculations at both the MP2/6-311+(d,p) and B3LYP/TZV+(3df,3p) levels of theory. High resolution FTIR spectra were recorded at room temperature and in an enclosive flow cell at a rotational temperature of 140 K. The cold spectrum was sufficiently resolved to enable rovibrational analyses of the overlapping ν4 (1200.7341 cm−1) and ν13 (1223.3 cm−1) bands, which have a/c hybrid and b-type character, respectively. Ground state combination differences were used to confirm assignment of 2375 lines to ν4 (Jmax = 86, Ka max = 50) and 2921 lines to ν13 (Jmax = 60, Ka max = 54). Effective rotational and centrifugal distortion constants were determined for ν4, and the polarization ratio was found to be . Severe Coriolis perturbations prevent any satisfactory fit to the ν13 band.  相似文献   

13.
Magnetic and electromagnetic wave absorption properties of α-Fe(N) nanoparticles, synthesized by chemical vapor condensation and then kept in air for 5 years, have been studied. The magnetic properties of the α-Fe(N) nanoparticles were slightly decreased because of the degradation in air. A slight increase in the thickness of oxide shells results in an excellent dielectric loss. The α-Fe(N) nanoparticles exhibited outstanding reflection loss (RL<−20 dB) in a 4.5-18 GHz for the absorber thicknesses of ~1-3.1 mm, and an optimal RL of −37.5 dB was obtained at 10.4 GHz with an absorber thickness of 1.6 mm. The broadest bandwidth (RL<−10 dB) from 13.3 to 17.4 GHz, covering almost the whole Ku-band, is obtained for a 1.2 mm layer.  相似文献   

14.
The Fourier transform gas-phase IR spectrum of 1,2,3-thiadiazole, C2H2N2S, has been recorded with a resolution of ca. 0.003 cm−1 in the 700-1100 cm−1 spectral region. Four fundamental bands ν6(A/; 1101.8 cm−1), ν7(A/; 1038.8 cm−1), ν9(A/, 858.9 cm−1), and ν13(A//; 746.2 cm−1) have been analyzed using the Watson model in A-reduction. Two additional bands, ν8 (A/; 894.6 cm−1) and ν12(A//; 881.2 cm−1) were assigned by their weak Q-branches. Ground state rotational and quartic centrifugal distortion constants as well as upper state spectroscopic constants have been obtained from fits. A number of weak global and local interactions are present in the bands. The resonances identified were qualitatively explained by Coriolis type perturbations with neighboring levels. Ground state rotational and quartic centrifugal distortion constants, anharmonic frequencies, and vibration-rotational α-constants predicted by quantum chemical calculations using a cc-pVTZ basis and B3LYP methodology, have been compared with the present experimental data, where there is generally good agreement.  相似文献   

15.
The Fourier transform gas-phase IR spectrum of 1,3,4-thiadiazole, C2H2N2S, has been recorded with a resolution of ca. 0.003 cm−1 in the 800-1500 cm−1 spectral region. Five fundamental bands ν2(A1; 1391.9 cm−1), ν4(A1; 964.4 cm−1), ν5(A1; 894.6 cm−1), ν9(B1; 821.5 cm−1), and ν14(B2; 898.4 cm−1) have been analysed using the Watson model. Ground state rotational and quartic centrifugal distortion constants as well as upper state spectroscopic constants have been obtained from fits. The ν4 and ν9 bands are unperturbed while a strong c-Coriolis resonance perturbs the close-lying ν5 and ν14 bands. This dyad system has been analysed by a model including first and second order c-Coriolis resonance using the theoretically predicted Coriolis coupling constant . The ν2 band is strongly perturbed by a local resonance, and we obtain a set of spectroscopic parameters using a model including second order a-Coriolis resonance with the inactive ν10 + ν14 band. Ground state rotational and quartic centrifugal distortion constants, anharmonic frequencies, and vibration-rotational α-constants predicted by quantum chemical calculations using a cc-pVTZ basis and B3LYP methodology, have been compared with the present experimental data, where there is generally good agreement.  相似文献   

16.
This paper reports the first assignment of rovibrational transitions of the 5ν4 and ν2+4ν4 band systems of 12CH4 in the 6287-6550 cm−1 region, which is usually referred to as part of the 1.58 μm methane transparency window. The analysis was based on two line lists previously obtained in Grenoble by cavity ring down spectroscopy at T=297 and 79 K completed by three long-path Fourier transform spectra recorded in Reims (at 290 K, L=1603 m, P=1-34 mbar). In order to determine the dipole transition moment parameters and quantify the intensity borrowing due to the resonance interactions, we had to include in the fit of the effective Hamiltonian model some lines of the stronger ν1+3ν4 and ν2+4ν4 bands. For this purpose, intensities of 179 additional lines were retrieved from FTS spectra above 6550 cm−1 though the analysis of these higher bands is not complete. About 1955 experimental line positions and 1462 line intensities were fitted with RMS standard deviations of 0.003 cm−1 and 13.1%, respectively. A line list of 8029 calculated and observed transitions which are considered as dominant was constructed for 12CH4 in the 6287-6550 cm−1 region. This is the first high-resolution analysis and modelling of 5-quanta band systems of 12CH4.  相似文献   

17.
As a further step in obtaining high performance elevated temperature self-lubrication anti-wear composite coatings on TiAl alloy, a novel Ni-P electroless plating method was adopted to encapsulate the as-received CaF2 in the preparation of precursor NiCr-Cr3C2-CaF2 mixed powders with an aim to decrease its mass loss and increase its compatibility with the metal matrix during a Nd:YAG laser cladding. The microstructure of the coating was examined using X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) and the friction and wear behavior of the composite coatings sliding against the hardened 0.45% C steel ring was evaluated using a block-on-ring wear tester at room temperature. It was found that the coating had a unique microstructure consisting of primary dendrites TiC and block Al4C3 carbides reinforcement as well as fine isolated spherical CaF2 solid lubrication particles uniformly dispersed in the NiCrAlTi (γ) matrix. The good friction-reducing and anti-wear abilities of the laser clad composite coating was suggested to the Ni-P electroless plating and the attendant reduction of mass loss of CaF2 and the increasing of it's wettability with the NiCrAlTi (γ) matrix during the laser cladding process.  相似文献   

18.
H2-broadening coefficients are measured for 41 transitions of PH3 in the QR branch of the ν2 band and the PP, RP, and PQ branches of the ν4 band, using a tunable diode-laser spectrometer. The recorded lines with J values ranging from 2 to 16 and K from 0 to 11 are located between 995 and . The collisional widths are determined by fitting each spectral line with a Voigt profile, a Rautian profile, and a speed-dependent Rautian profile. The latter model provides larger broadening coefficients than the Voigt model. These coefficients γ0(J,K) are found to decrease slightly on the whole as J increases and they decrease significantly for K values approaching or equal to J(J?4). The H2-broadenings are also calculated on the basis of a semiclassical model of interacting linear molecules, using an atom-atom Lennard-Jones potential in addition to the weak electrostatic contributions. The theoretical results are in satisfactory agreement with the experimental data and reproduce the J and K dependencies of the broadenings, but the decrease observed for the QR(J,K) transitions with K=J is notably overestimated.  相似文献   

19.
Spectra of CF4 in the ν4 fundamental band region have been recorded in pure gas and in mixtures with He, Ar and N2 at resolution up to . Obtained data allowed us to evaluate the integrated band intensity, line intensity distribution and effective broadening coefficients for J-multiplets. The broadening coefficient behavior is similar to that previously registered for linear molecules: they coincide for P and R branches; the J-dependence in the case of argon is more pronounced than that for helium. The broadening coefficients for nitrogen and helium are practically the same but the values for nitrogen are scattered around the general trend.Q-branch broadening is different from that for J-manifolds. The coefficients of branch broadening are noticeably smaller. Nitrogen broadening is very close to result for the case of argon though there is a marked difference between them for J-manifolds. Collisions with argon and nitrogen broaden the Q-branch almost 3 times more effectively than collisions with helium.  相似文献   

20.
The ν4 and the ν9 bands of CF2CH2 have been studied using coincidences with the 10.4 μm band of the CO2 laser and the 10.9 μm band of the N2O laser. These resonances have been analyzed, together with recent microwave results, to give the following vibration-rotation parameters and dipole moments in the ν4 and ν9 states
  相似文献   

ν4 CF2CH2ν9 CF2CH2
ν0925.7692 (2)953.8057 (2)cm?1
A10 971.99 (2)11 026.918 (6)MHz
B10 414.98 (2)10 436.381 (6)MHz
C5328.48 (2)5346.100 (6)MHz
μ1.382 (1)1.382 (1)D
μ - μ00.014 (2)0.004 (1)D
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