鲁玉明
,
范峰
,
蔡传兵
,
曹世勋
,
张金仓
无机材料学报
doi:10.3724/SP.J.1077.2008.00607
用电弧炉熔炼法制备了新的三元金属间化合物Ce5AgBi3, 用Rietveld方法对其结构进行了精修, 该化合物为Hf5CuSn3结构(空间群p63/mcm), 其中Ce、Ag和Bi分别占据Hf、Cu和Sn的位置, 晶胞参数为: a=b=9.7163(3)A, c=6.6228(2)A, V=541.47(5)A3. 该结构特点是沿着c轴方向的层状结构. 其中6g的Ce和Bi组成六边形网状平面结构, 2d的Ag和4f位置的Ce分别占据由Ce-Bi六边形所形成的沿着c轴方向的两种隧道中. 用PPMS对Ce5AgBi3的磁性和比热性能做了分析. 该化合物低温下为反铁磁性, 奈尔温度为3.8K, 高温时符合居里-外斯定律, 有效磁量子数为2.67μB, 表明其磁矩都是由Ce3+提供.
关键词:
金属间化合物
,
cerium
,
Ce5AgBi3
,
Rietveld method
张宁
,
沈玉龙
中国稀土学报
doi:10.11785/S1000-4343.20140315
合成了月桂酸镧/铈/钕,分别与硬脂酸钙、季戊四醇复配得到了硬质PVC用月桂酸稀土复合热稳定剂.采用刚果红法、转矩流变仪、动态力学谱仪等考察其对PVC热稳定性、流变性能、力学性能的影响,利用红外光谱初步探讨了其热稳定机制.结果表明:稀土复合热稳定剂中月桂酸镧(铈/钕)/硬脂酸钙/季戊四醇最佳比例为3∶1∶1;具有良好的热稳定性,静态、动态热稳定时间均达到为90和50 min以上;其加工性能和力学性能与铅盐体系相当,断裂伸长率明显高于铅盐体系.
关键词:
复合热稳定剂
,
镧
,
铈
,
钕
,
聚氯乙烯
,
月桂酸
Z.X. Yuan
,
S.H. Song
,
T.H. X.i
,
X.J. Zhangand Z.S. Yu(Department of Material
,
Wuhan Ye in University of Science and Technology
,
Wuhan 430081
,
China)(Department of Materials Physics
,
University of Science and Technology Beijing
,
Beijing 100083
,
China)
金属学报(英文版)
The infiuence of cerium on grnin boundaries of polycrpstalline N3Al alloys has beenstudied. The ja6mcability of a Ce-doped N3Al alloy strongly depends on the certumcontent. The alloy exhibits very poor fabrica6ility and cannot be fabrtcated into goodsheet8 by cold rolling when the concentmtion of cerium is <0. 0088wt% or>0.044wt%.A 0.011wt%Ce-doped N3Al alloy exhibits relatively good fabricability and may be fab-ricated into useful sheets by repeated cold rolling with 1OOa C annealing. The ductilityof the alloy strongly depends on the cerium distribution. Wthout the grain boundaryprecipitation of a second phase containing cer1um) the higher the segmpation level ofcerzum, the 6ettcr the tensile properties of the alloys, and in turn the more enhancedthe grain boundary cohesion.
关键词:
segregation
,
null
,
null
,
null
,
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