EFFECT OF CHROMIUM SUBSTITUTION ON STRUCTURAL AND MAGNETIC PROPERTIES OF R_2Fe_(17) COMPOUND

ＴｗｏｄｒａｗｂａｃｋｓｒｅｓｔｒｉｃｔｔｈｅａｐｐｌｉｃａｔｉｏｎｏｆｔｈｅＲ２Ｆｅ１７ｃｏｍｐｏｕｎｄｓａｓｐｅｒｍａｎｅｎｔｍａｇｎｅｔ：ｎｏｎｅｏｆｔｈｅｍｅｘｈｉｂｉｔｓａｎｅａｓｙｃａｘｉｓｍａｇｎｅｔｏｃｒｙｓｔａｌｌｉｎｅａｎｉｓｏｔｒｏｐｙａｔｒｏｏｍｔｅｍｐｅｒａｔｕｒｅａｎｄＣｕｒｉｅｔｅｍｐｅｒａｔｕｒｅＴｃｏｆｔｈｅｍｉｓｒｅｌａｔｉｖｅｌｙｌｏｗ．Ｉｎｒｅｃｅｎｔｙｅａｒｓ,ｖａｒｉｏｕｓｍａｇｎｅｔｉｃｍａｔｅｒｉａｌｓｂａｓｅｄｏｎＲ２Ｆｅ１７ｈａｖｅｂｅｅ…     

STRUCTURAL AND MAGNETIC PROPERTIES OF Ho_2AlFe_(16x) Mn_xCOMPOUNDS

Ｉｎｐｒｅｖｉｏｕｓｗｏｒｋ〔１〕,ｗｅｒｅｐｏｒｔｅｄｔｈａｔｔｈｅｒｈｏｍｂｏｈｅｄｒａｌｏｒｈｅｘａｇｏｎａｌ２：１７ｐｈａｓｅｓｔｒｕｃｔｕｒｅｃａｎｂｅｓｔａｂｉｌｉｚｅｄｂｙｒｅｐｌａｃｉｎｇＦｅｗｉｔｈＡｌ．ＴｈｅｓｉｎｇｌｅｐｈａｓｅｃｏｍｐｏｕｎｄｓｏｆＲ２ＡｌＦｅ１６ｘＭｎｘ（Ｒ＝ｒａｒｅｅａｒｔｈｅｌｅｍｅｎｔ）ｆｒｏｍｗｉｔｈＭｎｃｏｎｃｅｎｔｒａｔｉｏｎｕｐｔｏｘ＝８ｆｏｒＴｈ２Ｎｉ１７ｐｈａｓｅａｎｄｘ＝１６ｆｏｒＴｈ２Ｚｎ１７ｐｈａｓｅ．Ｉｎｔｈｉｓｗｏｒ…     

MAGNETIC PROPERTIES OF Nd_2(Fe_(1-x)M_x)_(14)B(M=C,Si)ALLOYS

The magnetic properties of Nd_2(Fe_(1-x)M_x)_(14)B(M=C and Si) compounds have been investi-gated.Substituting Fe by small amount of metalloid C and Si atoms,the compounds are intetragonal structure and have uniaxial anisotropy.The substitution of C for part of Fe de-creases the Curie temperature of the compounds and the intrinsic coercivity of bond samples atlow temperature.The replacement of Fe by Si makes the Curie temperature increase with amaximum at the vicinity of x=0.15.When the range of the content of Si is 0≤x≤0.10,thecoercivity distinctly increases at room temperature.from 62.7 kA/m at x=0 to138.7kA/m at x=0.06,where the residual magnetization has a maximum:in the mean timethe saturation magnetization decreases only by a small amount.     

MAGNETIC PROPERTIES AND CRYSTALLIZATION OF AMORPHOUS ALLOYS Co_(90-x)Cr_xZr_(10)

Curie temperature of amorphous alloys Co_(90-x)Cr_x Zr_(10) decreases linearly with increas-ing x.Average magnetic moment per magnetic atom Co or Cr is 1.51 μB or -3.62 μBrespectively.The temperature dependence of spontaneous magnetization at low temper-atures is in agreement with Bloch's T~(3/2) law.The spin wave stiffness constant decreaseswith increasing x from 4 to 20.The range of interaction is 2—3 atoms for x=4 andnearest neighbour atom for x=20.The crystallization temperature increases mono-tonically with increasing x.It may relate to the average number of outer electrons peratom.The crystalline phase components of heat-treated alloys were analyzed by X-raydiffration and thermomagnetic measurement.     

EFFECT OF ROTATIONAL FIELD ANNEALING ON MAGNETIC ANISOTROPY OF Fe_5Co_(73)Si_(10)B_(12) AMORPHOUS ALLOY

根据非晶态Fe_5Co_(73)Si_(10)B_(12)合金薄带不同方向磁化曲线与磁致伸缩曲线随退火状态的变化规律,发现Curie温度低于晶化温度的非晶态合金经旋转磁场热处理时,可以消除由于自发磁化场所感生的磁各向异性。初步分析和讨论了淬火态(制备)非晶态合金具有磁各向异性的原因。     

金属磁记忆法诊断的理论基础——铁磁性材料的弹—塑性应变磁化

电磁感应定律证明,铁磁性材料在地球磁场中的自发磁化来源于定向应力作用下材料本身的应变和交变应力作用下材料的非对称弹－塑性应变。某种铁磁性材料的自发磁化过程可由该材料的磁化和退磁曲线来估计,由此推得的磁弹性现象图与实验结果相一致。     

THE MAGNETIC PROPERTIES AND MOSSBAUER SPECTRA OF Y_2(Fe_(1-x)Ni_x)_(17)

实验发现,三元化合物Y_2(Fe_(1-x)Ni_x)_(17)的居里温度T_c随镍含量x变化,当x=0.3时,居里温度呈现极值,T_c=625K。为了研究镍原子部分地替代铁原子后对磁性的影响,取不同镍含量的样品,用X射线测定了易磁化方向,并在高于70千奥斯特的强磁场下,测量了饱和磁化强度随镍含量x的变化。为了研究镍原子在此种晶体中是否有序分布在特定位置上,观测和对比了Y_2Fe_(17)和Y_2(Fe_(0.9)Ni_(0.1))_(17)的穆斯保尔谱线。根据所得的实验结果,分析了居里温度随镍含量变化的原因。     

MAGNETIC MOMENT,CURIE TEMPERATURE AND SPIN WAVE EXCITATION FOR AMORPHOUS Fe_(90-x)Si_xZr_(10) ALLOYS

The magnetization curves at 1.5 K and thermomagnetic curves for amorphous Fe_(90-x)Si_xZr_(10)(x=0,4,7 and 10)alloys prepared by the drum spinning technique have been measured with an extracting sample magnetometer.It is obtained that the average magnetic moment,,per magnetic atom and Curie temperature,T_c,in the amorphous FeSiZr alloys increase with increasing Si content.The and T_c are found to be quite small,compared with amorphous FeSiB alloys.This unusual behavior is suggested to be due to the presence of the Fe—Fe antiferromagnetic interactions.The temperature dependence of magnetization at lower temperature is in accordance with Bloch's T~(3/2) law.Calculation shows that the spin wave stiffness constant,D,increases with increasing Si content from 0.37 meV·nm~2 for x=0 to 0.538 meV·nm~2 for x=10.The values ofindicate that the range of the exchange interaction is roughly the mean atomic distance of nearest neighbours.     

MAGNETIC PHASE DIAGRAM OF SmMn_2(Ge_(1-x)Si_x)_2 SYSTEM

1.IntroductionTheternaryRMn2X2compounds(Risrareearth,andXisGeorSi)crystallizeinthebodycenteredtetrag0nalThCr2Si2-typestructurewithspacegr0upI4/mmm,inwhichtheR,TandXatomsoccuPythe2a,4dand4csites,respectivelyl1t2].Theyexhibitillterestingmagneticpr0perties['].InSmMn2Ge2tlireedifferentmagneticorderingtypeshavebeendetermined:ferromagnetismfor153K相似文献   

MAGNETIC DOMAIN STRUCTURE AND RELATED MAGNETIC PROPERTIES OF(NdPr)_(16)Fe_(76)B_8 PERMANENT MAGNET

The magnetic domain structure and related magnetic properties of (NdPr)_(16)Fe_(76)B_8 permanentmagnet have been studied by colloid-SEM method.In thermally demagnetized state,the ma-trix grains in the magnet generally exhibit multidomain structure,i.e.,180° plate-like indi-vidual domain and a few spike-like or maze-like domains.The average width of the domainmeasured was 1.5μm.Grain size of single-domain was observed to be generally about 1μmand only a few up to 3μm.The results calculated are:the domain wall energy γ=36MJ/m~2,the exchange constant A=4.5×10~(-11)J/m,the domain wall width δ=15.7nm,and the critical grain diameter of single-domain D_c=0.5μm.The dependence of high magnet-ic field gradient at grain boundaries in different magnetization directions in the adjacent mag-netic domains located on both sides of grain boundaries and the effect of microstructure on thevalues of K,A and δ were discussed.     

磁粉探伤磁化技术与磁化设备

磁化技术的发展推动磁化设备的更新换代，综述单方向（周向，纵向）磁化，复合（摆动磁场，旋转磁场）磁化，多向（两组以上多个电源）复合或交替磁化的设备结构及特点，并介绍国外典型通用多向磁粉探伤设备的性能与应用。     

MAGNETIC PROPERTIES OF AMORPHOUS CoZr SOFT MAGNETIC FILMS

The amorphous CoZr soft magnetic films with superior properties were prepared byradio-frequency sputtering under pressure of 0.5Pa Ar.The saturation magnetization of theamorphous CoZr films with relation to the Zr content and temperature was investigated.Theamorphous CoZr films composed of different constituents obey the Bloch T~(3/2)-low in a widerange of temperatures.The number of electrons transferred from each Zr atom to 3d energyband of Co calculated by the rigid band model is about 2.27.     

Sm_2Co_(17-x)Ti_x化合物的结构和磁性

利用 Ｘ射线衍射和磁性测量研究了 Ｓｍ２Ｃｏ１７－ｘＴｉｘ化合物的结构和磁性实验表明这些化合物都具有 Ｔｈ２Ｚｎ１７型 结构, Ｔｉ替代 Ｃｏ不改变化合物的晶体结构,但引起晶格膨胀所有化合物在 Ｃｕｒｉｅ温度以下都表现为单轴磁晶各向异性随 着 Ｔｉ含量的增加,化合物的 Ｃｕｒｉｅ温度和饱和磁化强度都单调降低,而磁晶各向异性场在 Ｔｉ含量为 １．０时出现一极大值     

TbMn6—xCoxSn6赝三元化合物的结构和磁性

本文研究了ＴｂＭｎ６－ｘＣｏｘＳｎ和赝三元化合物的结构和磁性，结果表明：用Ｃｏ部分取代ＴｂＭｎ６Ｓｎ６中的Ｍｎ不改变其晶体结构，但随Ｃｏ含量的增加晶格常数和单胞体积单调减小；居里温度随Ｃｏ含昨增大而降低；自旋重取向温度也随Ｃｏ含量增大而降低，但Ｃｏ含≥０．６时自旋重取向消失；     

用Ga取代部分Fe对R3（Fe,Mo）29结构及磁性的影响

详细研究了Ｇａ取代Ｒ３（Ｆｅ,Ｍｏ）２９（Ｒ＝Ｓｍ,Ｙ）（Ｇａ＜０．１５）中的部分Ｆｅ对其结构和内禀磁性的影响,包括不同的Ｇａ取代对Ｒ３（Ｆｅ,Ｍｏ）２９化合物的晶胞常数、居里温度、饱和磁化强度、磁晶各向异性的影响。结果表明：在Ｒ３（Ｆｅ,Ｍｏ,Ｇａ）２９化合物中,随着Ｇａ含量的增加,晶胞体积膨胀,居里温度升高,饱和磁化强度下降,Ｆｅ原子的平均磁矩降低,Ｓｍ３（Ｆｅ０．９６６－ｘＭｏ０．０３４Ｇａｘ）２９化合物的各向异性由平面向锥面结构转变,继续增加Ｇａ含量,有可能出现单轴各向异性。     

腐蚀疲劳过程中裂尖阳极溶解对裂纹扩展的作用

在模拟腐蚀疲劳裂尖介质中,分别用铂丝和40CrNiMo钢为辅助电极测定了在不同拉伸速率下中温回火的40CrNiMo钢的腐蚀电流密度i_(a)与应变速率、塑性应变量的关系,其结果为:利用疲劳裂纹尖端应变的弹塑性有限元计算,得到腐蚀疲劳裂尖阳极溶解引起的裂纹扩展与△K的关系,结果表明:中温回火的40CrNiMo钢在3.5％NaCl水容液中裂尖阳极溶解对腐蚀疲劳裂纹扩展的直接贡很小,阳极溶解的主要作用是影响为裂尖断裂区氢致开裂提供氢原子的阴极过程。     

掺杂Ti对Fe－N薄膜结构与磁性的影响

用对向靶溅射仪制备出含多量Ｆｅ（１６）Ｎ２相的（Ｆｅ，Ｔｉ）－Ｎ薄膜，研究了掺杂Ｔｉ对Ｆｅ－Ｎ薄膜结构与磁性的影响，在溅射Ｆｅ－Ｎ薄膜时加入适量的Ｔｉ可提高Ｆｅ－Ｎ薄膜中Ｆｅ（１６）Ｎ２相的含量．Ｔｉ含量（原子分数）在０—２５％时薄膜饱和磁化强度均高于纯Ｆｅ的值；Ｔｉ浓度为１０％时，薄膜磁化强度高达２．６８Ｔ，比纯Ｆｅ的饱和磁化强度值高２０％．     

采用环状裂纹圆棒试样测定中低强度钢的断裂韧度

本文应用环状裂纹受拉圆棒试样的尺寸效应于测定中低强度钢的平面应变断裂韧度K_(IC)。所用试样的尺寸比标准试样小很多。用J积分分析了尺寸效应,并通过有限元计算和断口分析探讨了允许用较小尺寸的圆棒试样测定K_(IC)的原因。     

MEASUREMENT OF K_(IC)OF MEDIAN OR LOW STRENGTH STEEL USING ROUND BARS WITH CIRCUMFERENCIAL CRACK

The size effect of tension round bars with circumferential crack was described and used tomeasure the plane-strain fracture toughness K_(1c) of median or low strength steel.The size ofcylindrical specimen required for K_(1c) measurement is much smaller than that of standardspecimen.The J-integral values of the cylindrical sqecimens were calculated to characterizethe size effect.The finite element calculution and fracture morphology analysis have beenconducted to eyplain the fact that smaller cylindrical specimen could be used to measureK_(1c) of median or low strength steel.     

MAGNETIC PROPERTIES OF R 3(Fe, Mo) 29 N x (R=Sm OR Y) INTERSTITIAL NITRIDES

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＲ３（Ｆｅ,Ｍ）２９（Ｒ＝ｒａｒｅｅａｒｔｈ;Ｍ＝Ｔｉ,Ｖ,Ｍｎ,Ｍｏ,ｅｔｃ）ｃｏｍｐｏｕｎｄｓａｒｅｎｅｗｌｙｄｉｓｃｏｖｅｒｅｄｒａｒｅｅａｒｔｈｉｒｏｎｉｎｔｅｒｍｅｔａｌｉｃｓ．Ｔｈｅｙａｌｍｏｓｔｅｘｉｓｔ...