XU Wenchong SUN Fuyu Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing
,
China XU Wenchong Senior Engineer
,
Dept.No.13
,
Central Iron and Steel Research Institute
,
Ministry of Metallurgical Industry
,
Beijing 100081
,
China
金属学报(英文版)
The lattice constants and chemical composition of Ti,Nb and V precipitates with different particle sizes have been measured hy means of CBED and EDAX.It was obtained that the concentration ratio Of Nb and V,C_(Nb)/C_V,and the lattice constants in the Nb-V steel de- crease with the decrease of the particle size of the precipitates,but there is no regularity for tattice constant of Ti,N b and V precipitate against their particle size in the Ti-V-Nb steel.
关键词:
microalloyed steel
,
null
,
null
杨金瑞
,
余尚先
,
顾江楠
高分子材料科学与工程
通过对resol(羟甲基酚化合物和低分子量羟甲基酚树脂)DEPT135图谱的分析讨论,得到一系列计算resol微细结构参数的经验公式.根据DEPT135图谱可判断是否发生缩聚反应,根据经验公式可计算酚单体各个活性点参与反应百分率或酚羟基导入率、不同类型缩聚所占百分率及低分子量羟甲基酚树脂的平均核体数.
关键词:
羟甲基酚化合物
,
羟甲基酚树脂
,
DEPT135
,
结构参数
Physica Status Solidi B-Basic Research
The electronic structure of the 13-atom Rh cluster is studied with the structure model optimized by Estiu and Zerner using the discrete variational local-spin density-functional method. The magnetic moment per atom of the cluster is calculated to be 0.54 mu(B), in good agreement with experimental measurements (0.48 +/- 0.13)mu(B). It confirms our previous assumption that the structural distortion of the Rh-13 cluster from a perfect icosahedron to its ground state geometry decreases its magnetic moment and makes the theoretical calculation close to the experimental measurement.
关键词:
molecules
Journal of Applied Physics
Alloys of PrCo13-xSix (1.5 less than or equal to x less than or equal to 4.0) have been prepared by are melting and subsequent annealing. X-ray powder diffraction proved that the alloys crystallized in the cubic NaZn13-type structure for x=1.5, and in the tetragonal NaZn13-derivative one for x greater than or equal to 2.0. Their Curie temperatures are almost independent of the Si content. Their magnetization curves exhibit a binary-step characteristic. The ac susceptibility curve indicates that there exists a magnetic transition below room temperature. The anomalous binary-step magnetization curves and the ac susceptibility curves versus temperature suggest a metamagnetic transition. (C) 1994 American Institute of Physics.
关键词:
王利刚
,
特古斯
稀土
NaZn13型晶体结构的La(Fe,Si)13化合物由于具有原料价格低廉、磁热效应巨大、环保等优点而备受关注,已经成为国际上公认的最有潜力的室温磁制冷材料之一.本文系统介绍了La(Fe,Si)13化合物的结构和磁热性能,阐述了吸氢、吸氮,稀土元素、Co、B、C、Ca等替代元素对该系列化合物结构和磁热性能的影响,评述了最新的La(Fe,Si)13化合物的制备和加工工艺,最后展望了La(Fe,Si)13化合物作为磁制冷材料的发展趋势.
关键词:
磁制冷
,
磁热效应
,
La(Fe,Si)13化合物
,
磁熵变
叶四友
,
刘建永
,
杨伟
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2015.08.015
目的：研究获得高质量H13激光涂层的工艺。方法以H13合金粉末为熔覆材料,在H13钢退火基体表面制备H13合金涂层,采用均匀设计试验,利用金相法检测涂层的几何形貌参数,得到涂层宽度回归模型,并验证所建立模型的准确性。利用光学显微镜和扫描电镜分析涂层的显微组织形貌,对涂层成分进行分析,通过显微硬度计测试涂层截面的显微硬度分布。对涂层气孔、裂纹和成分偏析进行分析。结果扫描速度22 mm/s ,激光功率1300 W,送粉速率21 g/min时,H13合金涂层与基体呈良好的冶金结合,涂层内组织均匀致密,无裂纹缺陷,截面显微硬度约600~699HV,是H13基体硬度的2.4~3倍。扫描速度14 mm/s ,激光功率1400 W,送粉速率42 g/min 时,涂层的截面显微硬度约为669~698HV,是基体的2.85~3倍。结论在两种工艺条件下,均能获得质量较优的H13合金涂层。
关键词:
激光熔覆
,
H13合金涂层
,
几何形貌
,
均匀设计
,
回归模型
,
显微硬度
Physica Status Solidi a-Applied Research
The crystal structure and magnetic properties of LaCo13-xAlx compounds have been investigated by X-ray powder diffraction and magnetization measurement. X-ray powder diffraction shows that the compounds crystallize in cubic NaZn13-type structure with lattice parameter a=11.345(2) to 11.473(4) Angstrom in the range of x less than or equal to 2.7, and in the tetragonal Ce2Ni17Si9 structure at x=3. Magnetization measurements reveal that both cubic and tetragonal LaCo13-xAlx are ferromagnetic with Curie temperature higher than 840 K, and the magnetic moment per Co atom in LaCo13-xAlx compounds decreases with Al content.
关键词:
intermetallic compounds;rare-earth;transition
付艳艳
,
周廉
,
于振涛
,
王克光
稀有金属
doi:10.3969/j.issn.0258-7076.2004.01.010
研究了Ti-13Nb-13Zr合金在β相区和(α+β)两相区固溶和时效处理后其合金力学性能及组织变化规律. 分析发现在β相区固溶的合金, 水冷时生成针状马氏体α′, 空冷时生成亚稳定β相和少量αp, 在(α+β)两相区固溶生成β转和αP. 在β相区和(α+β)两相区固溶试样经时效后, 晶粒内部主要析出点状和棒状αS. 在750 ℃/1 h固溶(WQ)和低温510 ℃/6 h时效的合金抗拉强度高、塑性较高、弹性模量低, 可以满足人体植入要求.
关键词:
Ti-13Nb-13Zr
,
力学性能
,
显微组织
田伟红
,
郭杨阳
,
李轩鹏
,
郭亚鑫
,
范爱兰
,
刘小萍
,
唐宾
表面技术
doi:10.16490/j.cnki.issn.1001-3660.2015.05.011
目的：提高医用钛合金的耐磨损性能。方法应用等离子渗氮技术在Ti13 Nb13 Zr基材上制备改性层,并对改性层组织、成分及硬度进行测试。利用往复磨损试验机研究改性层在干摩擦条件下的摩擦磨损性能,并与未处理的基材进行对比。结果 Ti13 Nb13 Zr合金表面经渗氮后形成致密均匀的改性层,硬度高达1110 HV0.025,改性层的磨损体积约为基材的1/23。结论等离子渗氮技术有效地改善了Ti13 Nb13 Zr合金的摩擦磨损性能。
关键词:
Ti13 Nb13 Zr
,
等离子渗氮
,
硬度
,
摩擦性能
张成路
,
申洪江
,
邹立伟
,
许永廷
,
广东
,
李元东
,
王杨
,
王利东
应用化学
doi:10.3969/j.issn.1000-0518.2009.10.011
以3,5-二甲氧基苯甲酸(1)为起始原料, 经过甲醇酯化、氢化铝锂还原、四溴化碳溴代和Wittig-Horner反应,高产率的合成了Wittig-Horner试剂(5). 化合物5与对羟基苯甲醛(6)的羟基保护产物(7)偶联得到化合物(8),后者经去甲氧基亚甲基保护和仿生氧化偶联反应成功地全合成了(E)-脱氢二聚白藜芦醇-11,11′,13,13′-四甲醚(10). 通过~1H NMR、~(13)C NMR、IR、HRMS等测试技术确定化合物10为二聚芪类化合物(E)-脱氢二聚白藜芦醇-11,11′,13,13′-四甲醚,总收率48.93%.
关键词:
白藜芦醇
,
氧化偶联
,
二聚芪类化合物
,
(E)-脱氢二聚白藜芦醇四甲醚
