Mustafa Ulutan Osman N. Celik Hakan Gasan Umit Er
材料科学技术（英文）
In this study, the effects of various surface treatments on the friction and wear behavior of AISI 4140 steel have been evaluated. Sample surfaces of AISI 4140 steel were treated by quenching, carburizing, boronizing and plasma transferred arc (PTA) modification. The microstructural characteristics of surface treated steel samples were examined by optical microscopy and scanning electron microscopy (SEM). The mechanical properties of the samples including the surface roughness, microhardness, and abrasive and adhesive wear characteristics were also evaluated. Wear tests were applied by using a block-on-disc configuration under dry sliding conditions. The wear behavior and friction characteristics of the samples were determined as a function of sliding distance. Each sample group was compared with the other sample groups, and it was observed that
the carburized samples demonstrated the lowest weight losses; however, PTA-treated samples demonstrated the lowest coefficient of friction in comparison to the other sample groups at the same sliding distance.
关键词:
AISI 4140 steel
Journal of Applied Physics
Room-temperature 1.54 mum electroluminescence (EL) was compared for Au/SiO2:Er/n(+)-Si and Au/SiOx:Si:Er/n(+)-Si diodes under reverse bias. The 18 nm thick SiO2:Er and SiOx:Si:Er films were deposited by the magnetron sputtering technique. The maximum of the EL intensity was reached after annealing at 900 degreesC (SiO2:Er) and 800 degreesC (SiOx:Si:Er). The threshold potential of the EL was about 4 and 6 V for the Au/SiOx:Si:Er/n(+)-Si and Au/SiO2:Er/n(+)-Si diodes, respectively. The power efficiency was larger for the Au/SiOx:Si:Er/n(+)-Si diode than that for the Au/SiO2:Er/n(+)-Si diode by six times. Our experimental results demonstrate that the existence of Si nanoclusters reduces the threshold potentials of the EL and strongly enhances the power efficiency for Er3+ EL. (C) 2001 American Institute of Physics.
关键词:
molecular-beam epitaxy;erbium;si;photoluminescence;diodes
Solid State Communications
Er-doped Si-rich SiO2 (SRSO:Er) films have been deposited on n(+)-Si substrates by the magnetron sputtering technique, and both photoluminescence (PL) and electroluminescence (EL) at 1.54 mum have been observed from the films at room temperature. Dependence of pi, and EL intensities on the excess-Si content and annealing temperature has been studied. It is found that proper Si content and annealing temperature can evidently enhance EL intensity. An SRSO:Er film with 20% excess Si (area ratio of the Si target to the whole target) had more intense EL than a SiO2:Er film without excess Si, both annealed at 800 degreesC, by a factor of 5. This fact clearly demonstrates that energy coupling between Si nanometer particles and Er3+ ions also exists in the EL process as well as in the PL process. Experimental results also indicate that crystallization is not a prerequisite for NSPs enhancing luminescence in SRSO:Er films. The PL and EL spectra of the SRSO:Er films have much broader full widths at half maximum (FWHM, similar to 60 nm) than those of the other Er-doped materials reported. This wide FWHM can perhaps be used in wavelength division multiplexing in optical communication in future. (C) 2001 Elsevier Science Ltd. All rights reserved.
关键词:
thin films;nanostructures;recombination and trapping;luminescence;molecular-beam epitaxy;oxygen-doped silicon;erbium;nanocrystals;light;oxide
Chinese Physics Letters
Er3+-doped and Yb3+/Er3+ co-doped Gd3Sc2Ga3O12 (abbreviated as Er:GSGG and Yb,Er:GSGG, respectively) laser crystals are investigated by using a combination of spectroscopic measurements and thermal characterizations. An absorption peak of Yb, Er: GSGG crystal shifts to 970 nm and its absorption band broadens obviously, which makes the crystal suitable for pumping by a 970 nm laser diode (LD). This crystal also exhibits a shorter lifetime of a lower laser level, a larger emission cross section and higher thermal conductivity than those of Er: GSGG. All these factors suggest that Yb3+/Er3+ co-doping has a positive effect on improving the spectroscopic and thermal performances in GSGG based laser crystals, and imply that double-doped Yb, Er: GSGG crystal is a potential candidate as an excellent LD pumped 2.79 mu m laser material.
关键词:
mu-m;energy-transfer;gsgg laser;er3+;yag;irradiation;absorption;spectra;ysgg;yb3+
Zeitschrift Fur Metallkunde
A systematic reexamination of the Er - Co system was carried out by differential thermal analysis, optical microscopy, X-ray diffraction and EPMA techniques. A revised Er - Co binary phase diagram is proposed. This binary system consists of four peritectic reactions, three reactions of congruent melting and a eutectoidal reaction. The four peritectic reactions result in the formation of Er3Co, ErCo2, Er2Co7 and ErCo5, respectively. The three congruent reactions involve the formation of almost-equal-to Er16Co9, ErCo3 and Er2Co17. The eutectoidal reaction involves the decomposition of ErCo5 into Er2Co7 and Er2Co17. There are also four eutectic reactions in this system. The solid solubility of Er in Co is extremely small.
关键词:
intermetallic compounds
赵中魁
,
周铁涛
,
刘培英
,
陈昌麒
稀有金属材料与工程
采用TEM对5.6%Zn,1.9%Mg,1.6%Cu,1.0%Li,0.3%Er(质量分数)合金中的Er相进行研究,发现Er在合金中主要以AEr形式存在,Al3Er在合金中的形状为块状、点状、片状或蠕虫状,部分Al3Er与铝合金基体共格.细小的Al3Er可作为η相异质形核的核心.Er在合金的晶界有很大的偏析,而且晶界处Al3Er的存在,使该处晶界析出物不连续.
关键词:
Er
,
AEr
,
晶界
朱世旦
,
黄晖
,
聂祚仁
,
文胜平
,
张志军
稀有金属
doi:10.3969/j.issn.0258-7076.2009.02.006
采用金属型水冷模铸造制备了不同含铒量的Al-Er二元合金,通过对铸态及均匀化处理后实验合金的金相观察、电子探针(EPMA)以及透射电镜分析,研究了对不同含量的Er在AI-Er合金中的存在形式及固溶Er在纯铝中的固溶度.结果表明,在本实验条件下铒元素以过饱和固溶体形式存在于α-Al中和以Al3Er化合物的形式分布在晶界上,另外Er在铝基体的最大固溶度为O.1%(质量分数).
关键词:
铝铒合金
,
固溶度
,
EPMA
,
Al3Er相
Journal of Applied Physics
Samples of R2Fe17C(y)N(x) (R = Y, Sm, Er, Tm) were prepared by arc melting appropriate amount of R, Fe, and C, vacuum annealing at 1373 K and finally annealing at 740 K in nitrogen for 10 h. The magnetic properties of these compounds were investigated by means of ac initial susceptibility, magnetization measurements, and x-ray diffraction. The thermal stability of the nitride phase was studied by differential scanning calorimetry. It was found that, when heated above 600 K, R2Fe17C(y)N(x) irreversibly decomposes N which is irrespective of the carbon concentration and rare-earth element. The Curie temperatures of R2Fe17C(y)N(x) are independent of the carbon concentration and are approximately 400 K higher than those of the corresponding pure R2Fe17 compounds. However, the Curie temperatures cannot be correlated to the composition x of the initial R2Fe17C(y)N(x) compounds at room temperature because some N was lost during the heating to T(c). In the Er and Tm compounds spin reorientation transitions were found, marking the change of the easy magnetization direction from the c axis to the basal plane with increasing temperature. The Tm compounds show an additional magnetic transition at low temperatures (below 40 K). A coexistence of the hexagonal and the rhombohedral structural modifications was found in Er2Fe17C(y)N(x) when y < 1.5, characterized by two different spin reorientation temperatures. The anisotropy fields of Sm2Fe17C(y)N(x) are higher than that of Sm2Fe17N(x). Indications of a magnetic phase transition were found also in Sm2Fe17C0.7N(x) and Sm2Fe17C0.9N(x).
关键词:
magnetocrystalline anisotropy;carbides;alloys
余胜文
,
王为
,
杨军军
,
邹景霞
,
聂祚仁
中国稀土学报
通过应用Miedema热力学模型方法对添加了微量Er的Al-5Mg合金中的Er的存在形式进行了初步的分析,并结合XRD,TEM试验进行了验证.微量Er在Al-5Mg合金中主要是以Al3Er的形式存在,并且不会出现元素Mg与Er之间的金属间化合物;同时通过XRD和TEM分析证实,含微量Er(0.1%～0.7%)的Al-5Mg合金中Er是以Al3Er相存在并且弥散分布,讨论了Al3Er相与Al基体之间的取向关系,分析了Al3Er相的存在能够改善Al-5Mg合金材料的机械性能.
关键词:
Er
,
Al3Er
,
Al-Mg合金
,
热力学计算
,
稀土
