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51.
52.
对1Cr18Ni12Mo2Ti奥氏体不锈钢在稀土催渗条件下进行了加与未加辅助铁板的离子硫氮共渗对比试验.试验表明:稀土具有很强的催渗作用.在与辅助铁板的共同作用下,可使奥氏体不锈钢的氮化温度降低60℃,减小了零件的变形;在相同的共渗温度条件下,可使氮化层深度比离子硫氮碳共渗增加30%以上,比未加辅助铁板的稀土离子硫氮碳增加10%.且稀土元素可渗入钢表层,细化渗层组织,促进氮碳化合物弥散细小析出,提高渗层硬度. 相似文献
53.
M. Palumbo G. Borzone S. Delsante N. Parodi G. Cacciamani R. Ferro L. Battezzati M. Baricco 《Intermetallics》2004,12(12):442-1372
An optimised set of thermodynamic parameters for the Ce–Ni system has been obtained using the CALPHAD approach. A thorough thermodynamic analysis of the system has been carried out using different calorimetric techniques and the data have been used in the assessment. The free energy of the liquid phase has been described as a function of temperature and composition using a Redlich–Kister polynomial. Solid compounds have been considered as stoichiometric with the exception of the Laves phases. The phase diagram and thermodynamic quantities calculated from assessed parameters agree well with experimental data. 相似文献
54.
Bo Zhou Zhengfei Gu Junqin Li Gang Cheng Jun Cheng Chengfu Xu Lei Ma 《Journal of Alloys and Compounds》2007,430(1-2):132-135
A portion of the isothermal section (1173 K) of the phase diagram of the Gd–Co–Al ternary system (up to 33.3 at.% Gd) were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS) techniques. Fourteen single-phase regions (including solid solution regions of the binary compounds), twenty-five two-phase regions and twelve three-phase regions were found to exist at this isothermal section. In the GdCo2–GdAl2 system, the existence of the GdCo0.74Al1.26 phase is identified and it has a composition range of 30–45 at.% Al, the maximum solid solubility of Al in GdCo2 is about 15 at.%, and Co in GdAl2 is about 16 at.%. Besides, the maximum solid solubility of Al in Co, Gd2Co17 and GdCo5 is about 6, 17 and 25 at.%, respectively, the maximum solid solubility of Gd in Co, CoAl is below 2 at.% and the solid solubility range is from 47 to 61 at.% Al in CoAl phase. In this work, no new ternary compounds were observed. 相似文献
55.
稀土La对3Cr2W8V热作模具钢组织和性能的影响 总被引:6,自引:1,他引:6
研究了在3Cr2W8V热作模具钢中分别加入3种不同含量稀土La后,对组织、强度、硬度、冲击韧度和塑性的影响,并在相同的热处理工艺条件下,与不添加稀土La的3Cr2W8V钢进行对比。研究结果表明:稀土La加入量在适当的范围内可使组织得到明显细化,强度、冲击韧度和塑性有显著提高而硬度无明显变化,当稀土La加入量为0.20%时,3Cr2W8V钢可获得最好的综合力学性能。 相似文献
56.
57.
Zhongmin Yang Shiqing Xu Lili Hu Zhonghong Jiang 《Journal of Alloys and Compounds》2004,370(1-2):94-98
Yb3+–Er3+ co-doped Na2O–GeO2–PbO glass suitable for developing optical fiber lasers and amplifiers has been fabricated. The energy transfer efficiency from Yb3+ to Er3+ was investigated in the glasses with different Yb3+–Er3+ concentration ratios and the maximum energy transfer efficiency was found to be 67% at the Yb3+–Er3+ concentration ratio of 5:1. Subsequently, the studies of upconversion emissions in the visible range were performed. An intense green together with a relatively weak red emission was observed under the excitation of 976 nm diode laser. The quadratic dependence of the green emission on excitation power indicates that a two-photon absorption process occurs under a 976 nm excitation. However, for the red emission the slope of log-log plot of integrated intensity versus pump power declines with increasing Yb3+ ions content, indicating it is not resulted from a biphotonic process. 相似文献
58.
Key experiments were carried out on the three Al–R–Mg (R=Gd,Dy,Ho) systems and the results obtained used for the thermodynamic optimisation reported in a separate paper in this issue [Caccasmani G, De Negri S, Saccone A, Ferro R. Intermetallics this issue.]. The samples were characterized by differential thermal analysis (DTA), X-ray powder diffraction (XRD), light optical microscopy (LOM), scanning electron microscopy (SEM) and quantitative electron probe microanalysis (EPMA). The isothermal sections at 400 °C are all characterized by extended homogeneity regions at a constant rare earth content. The extension of the (Mg,Al)R solid solution, cP2-CsCl type, varies with the R atomic number. Ternary compounds (τ) of Al2(R,Mg) stoichiometry (hexagonal Laves phases with MgNi2-type structure) have been found to exist at 400 °C in all the systems. Their temperatures of formation were detected by DTA measurements. 相似文献
59.
60.
Microporous rare-earth coordination polymers constructed by 1,4-cyclohexanedicarboxylate 总被引:1,自引:0,他引:1
In this paper, three novel microporous materials of 1, 4-cyclohexanedicarboxylate Ln[(C8H10O4)1.5(H2O)] · 0.5(H2O) (Ln = Eu for 1, Nd for 2, Sm for 3) are synthesized by the hydrothermal method. The powder X-ray diffraction patterns demonstrate three complexes are isomorphism. The crystal structure of the coordination polymer 1 reveals that the Eu3+ ion center is located in the nine-coordinated environment and the carboxyl groups chelate Eu3+ ions to form 1-D channels through c-axis in μ1, μ2 and μ3 fashion. The properties of the microporous materials are all characterized by the adsorption and desorption of the nitrogen gas and show tremendous difference. TGA illustrate the open frameworks are stable to about 450 °C and they are retained upon removal of water molecules in channels. 相似文献