Crystalline Behavior and Magnetic Properties of Nd60Fe30-x Al10Cox（x = 0,5,10） Bulk Amorphous Alloys

Crystalline behavior and magnetic properties of Nd60Fe30-xAl10Cox( x = 0, 5, 10) bulk amorphous alloys were investigated by differential scanning calorimeter (DSC), X-ray diffraction (XRD) and the vibrating sample magnetometer (VSM). Neither glass transition nor supercooled liquid region before crystallization was observed for the as-cast Nd60Fe30-xAl10Cox ( x = 0,5,10) bulk amorphous alloys. The glass forming ability can be improved significantly by the addition of Co. The as-cast Nd60Fe30-xAl10Cox (x = 0,5,10) alloys show hard magnetic behavior. With the addition of Co content, intrinsic coercivity (iHc) increases while the saturation magnetization(σs) and remanence (σr) decrease. The Curie temperature for the as-cast Nd60Fe30-xAl10Cox alloys increases from 451 K for x =0 to 468 K for x = 10. Some pre-cipitation of crystalline phases does not affect the hard magnetic properties of Nd60Fe30-xAl10Cox(x = 0,5,10) alloys, while the hard magnetic behavior disappears quickly after the alloys being completely crystallized.     

TbCo／Cr Amorphous Film with Perpendicular Magneto-Anisotropy

Amorphousrareearth transitionmetalalloy (RE TM)films[1] havebeenintensivelystudied .Sincetheamorphousfilmsoftenpossessaverylargeuniaxialanisotropywithitseasyaxisperpendiculartothefilmplane ,theycanbeusedasmagneto optical[2 ] orhy bridrecordingmedia[3] .Amongthosefilms ,Tb Cofilmsareofgreatinterestbecauseoftheirhighcoer civeforce ,largeperpendicularanisotropyandeasycontroloftheirsaturationmagnetizationthroughcom positionadjustment[4 ] .However ,theTb Cofilmshavesuchadisadvantagethatsubstrate…     

新型(Fe,Co)-Zr-RE-B非晶合金的热稳定性和磁性

利用旋铸技术制备了一种新型的含稀土元素的铁基非晶合金。研究了Nd含量对Fe70Co8Zr7-xNdxB15(x=0～6%原子数分数)合金的非晶形成能力、热稳定性和磁性能的影响。当该合金系的Nd含量在0～6%(原子数分数)变化时,其饱和磁感应强度(Js)在1.10T～1.37T范围内变化,矫顽力(Hc)在2.28A/m～8.15A/m范围内变化。Js随Nd含量的增加而增加,当Nd含量为2%和3%时,其Hc值均在3A/m以下,且在Nd含量为2%时,具有最高的非晶形成能力(glassformationability简称GFA)即大的ΔTx(达61K);同时又有良好的软磁性能,其Js和Hc值分别为1.25T和2.28A/m。经对比得出,Fe70Co8Zr5RE2B15(RE=Ce、Pr、Gd和Tb)合金与Fe70Co8Zr5Nd2B15具有相近的非晶形成能力和磁性能。     

Phase Transformation Behaviors and Effects of Terbium in Polycrystalline Ni-Mn-Ga Magnetic Shape Memory Alloys

The phase transformation behaviors of two kinds of magnetic shape memory alloys NisoMn25 x Ga25-x and Ni50 Mn29Ga21-x Tbx were studied. When the composition of Ni in these alloys was constant, increasing Mn and reducing Ga contents make martensitic transformation temperatures rise obviously. Simultaneously, thermal hysteresis of phase transformation reduce but Curie temperature una|ters. When terbium was added, phase transformation temperature went up further and Curie temperature kept constant. The alloys still show strong ferromagnetism and properties of thermoelastic martensite phase transformation.     

水溶液中电沉积非晶态稀土合金的研究进展

稀土元素的还原电位很负，在水溶液中很难沉积。如何使其正移是实现稀土合金电镀的关键。分析了络合剂对稀土合金电沉积的影响，恰当的络合剂不但起到稳定镀液的作用，而且能使稀土的沉积电位显著正移。研究了非晶态合金电沉积的特点，利用二维Miedem坐标(△Φ^*和△nws^-1／3)以及加入尺寸因素(△R／RA)构成的三维化学坐标分析了水溶液电沉积非晶态稀土合金的形成规律。     

稀土对非晶态RuB/膨润土合金催化剂性能的影响

采用气相脉冲法,首次将非晶态RuB/Bn(膨润土)合金催化剂用于催化丙酮常压气相加氢反应。结果表明RuB/Bn催化剂低温下就表现出了很高的活性及生成异丙醇的选择性。稀土元素Nd、Eu、Er的加入提高了RuB合金催化剂的活性,异丙醇的产率也有一定程度的提高。用程序升温还原(TPR)、程序升温脱附(TPD)、等离子体发射光谱(ICP)等方法对催化剂表面性质及含量进行了表征,结果表明稀土元素的加入改变了催化剂的组成,使钌物种易于还原,而且增加了催化剂的氢吸附量。     

Crystallization and Microstructure Evolution of Amorphous Al85 Y4 Nd4 Fe7 Alloy

A rapidly solidified Al85Y4Nd4Fe7(%, in nominal atomic fraction) alloy was prepared by melt spinning. Asquenched and as-annealed microstructures were studied by differential scanning calorimetry (DSC), X-ray diffraction(XRD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Fully amorphous structure could be obtained in the rapidly solidified Al85Y4Nd4Fe7 alloy ribbons. The temperature of first crystallization exceeds 300℃. Crystallization of as-annealed Al85Y4Nd4Fe7 alloy is shown to occur in two stages : ( 1 ) primary crystallization of α-Al; (2) formation of Al3Y, Al13Fe4 and unknown crystalline phases.     

Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy

Magnesiumalloysarewidelyusedinweaponin dustry,spacenavigationandhavegoodpotentialof applicationanddevelopmentindailycommunication facilitiesduetotheirpropertiesoflightweightandhighstrength[1].Appliedasstructuralmaterials,mag nesiumalloysmayeasilycrackduet…     

FeCuNbSiB-La非晶软磁合金的静态磁性能

对于不同稀土加入量的非晶软磁合金的静态磁性能与热处理制度和稀土加入量的关系做了比较。结果表明，稀土加入量较高的合金其相应最佳性能（矫顽力较低）的热处理温度稍高，温度区间要窄。稀土加入量为１ａｔ％的非晶软磁合金的初始磁导率可达１．７×１０４。     

Effect of Lanthanum on Performance of RuB Amorphous Alloy Catalyst for Benzene Selective Hydrogenation

Benzene selective hydrogenation to cyclohexenehas aroused considerable interest among both indus-tries andresearchers as well inthe hope of establishinga new process for producing cyclohexanol via cyclo-hexene hydration .Cyclohexanol is the basic rawmate-rial in the production of polyamides nylon-66 , whichis produced by the polymerization of adipic acid withhexamethylendiamine .In this process ,the theoreticalconsumption of hydrogen is reduced to one-third andfewundesirable by-products are fo…     

Evaluating Acceleration Ability of Electrons of SiO_2 and ZnS in ZnS∶Er Electroluminescence

SinceCoeyandSun[1]discoveredtheinterstitial compoundSm2Fe17Nx,ithasattractedmanyresearch ers′attention.Asakindofpermanentmagneticmate rial,Sm2Fe17Nxexhibitsfairlyhighsaturationmagneti zation(1.54T)[2],highanisotropyfield(14T)under roomtemperatureandhighC…     

Evolution of Sm2Fel7 Alloys during Hydrogenation-Disproportion Process

The evolution of phase compositions, phase change and microstructure in Sm2Fe17 alloys during hydrogenationdisproportion process were systematically studied with XRD, SEM, EDX methods. Research indicates that HD process of Sm2Fe17 alloys is as follows： Sm2Fe17 alloy absorbs hydrogen first in the atmosphere of hydrogenation with a pressure of 0.1 MPa. Disproportionation begins at T ≥ 500 ℃, then the alloys tuna into lots of SmHx and α-Fe phases which are partly in microcrystal or amorphous structures. Along with the increase of temperature, the microcrystal and amorphous structures transformed into crystal structure and this transformation thoroughly completed at 750 ℃. The size of obtained crystal grain is about 20 - 100 nm. Based on the experimental data, a microstructural transformation model of Sm2Fe17 alloys during hydrogenation-disproportion process was made.     

Martensitic Transformation and Magnetic-Field-Induced Strain in Ni-Mn-Ga-RE （RE = Tb, Sm） Alloys

The effects of microamount additions of RE (Tb, Sm) on martensitic transition, the magnetic-field-induced strain and the bending strength of highly textured polycrystal line Ni4sMn33Ga19 alloy were investigated. The experimental results show that the addition of RE elements decreases the martensitic transformation temperature and the Curie temperature. But the bending strength of Ni-Mn-Ga-RE (RE=Tb, Sm) alloys increases remarkably because of the grain refinement. As a result, Ni-Mn-Ga-RE alloys will be applied practically with higher reliability and stability due to favorable plasticity and toughness. In addition, the replacement of small amounts Ga by Tb or Sm decreases the magnetic-field-in-duced strain of the alloys at room temperature.     

Effects of Heavy Rare Earth Elements on Properties ofAmorphous NiB Alloy Catalyst

Gas-phase hydrogenation of benzene was selected as probe reaction to study the effects of heavy rare earth ele-ments on the catalytic activity and sulfur resistance of amorphous NiB alloy. XRD, DSC, CO chemical adsorption, TPR and TPD were used to characterize the bulk and the surface properties of the alloys, respectively. The results indicate that the addition of a small amount of heavy rare earth (HRE) elements obviously improves the activity, thermal stability and sulfur resistance of amorphous NiB alloy. The HRE can alter H2 adsorption bond strength, increase the surface area of ac-tive nickel and the number of active centers over the surface of NiB alloy and it also can decrease the activation energy of NiB alloy for benzene hydrogenation. There are four kinds of adsorbing sites over the surface of NiB and NiBRE, only three kinds of them have concerned with the reaction.     

Structure and Magnetocaloric Effect in Tb（ Co1-xSnx）2 Alloys

Recently,researchonmagnetocaloriceffect(MCE)hasattractedagreatdealofinterestinrare earth(RE)basedcompoundsbecauseoftheirenergy efficiencyandenvironmentalsafetyformagneticrefrig eration.Afirst ordermagneticphasetransitionwas foundintheintermetalliccompoundsRECo2(RE=Er,Ho,Dy)withMgCu2typestructure[1,2],leadingtoa largemagneticentropychangeforthesecompounds,whereasasecond ordertransitionwasfoundinTbCo2andGdCo2.IntheintermetalliccompoundsRECo2,theloweringofd electronconcentrationbythesubst…     

大块锆基非晶合金电化学耐腐蚀行为的试验研究

利用电化学极化曲线方法研究了Zr41Ti14Cu12．5Ni5Be22．5Fe5非晶合金及成分相同的晶化合金及纯Zr在硫酸溶液中的腐蚀行为。利用减重法研究了Zr41Ti14Cu12．5Ni5Be22．5Fe5非晶合金及成份相同的晶化合金在浓硫酸溶液中的腐蚀行为。极化曲线测试结果表明，非晶合金及成分相同的晶化合金与纯金属Zr有很大差异：非晶合金过钝化电位最高，钝化区最长，而纯金属Zr过钝化电位最低；钝化区也最短。减重试验表明，非晶合金的腐蚀速率是成分相同晶化合金的1/4。以上结果表明非晶合金拥有优良的耐腐蚀性能。     

铁基非晶态合金的退火脆性

本文研究Fe₈₀B_20-xSi_x(x=6,8,10,12)非晶态合金的退火脆性规律,给出了合金成分原料纯度,薄带厚度以及薄带表面状态对非晶态合金退火脆性的影响。铁基非晶态合金在低温退火过程中已明显变脆。这种退火脆性是由非晶态合金亚稳特性决定的结构弛豫所致。     

Effect of Cerium on Chemical Short Range Order of Al-Fe-Ce Amorphous Alloy

Ｉｎｒｅｃｅｎｔｙｅａｒｓ,Ｈｅｅｔａｌ.[1]ａｎｄＩｎｏｕｅｅｔａｌ.[2]ｄｉｓｃｏｖｅｒｅｄａｇｒｏｕｐｏｆａｍｏｒｐｈｏｕｓａｌｌｏｙｓｗｉｔｈａｌｕｍｉｎｕｍｃｏｎｔｅｎｔｃｌｏｓｅｔｏ90%(ａｔｏｍｆｒａｃｔｉｏｎ),ｗｈｉｃｈｐｏｓｓｅｓｓｅｘｃｅｌｌｅｎｔｓｐｅｃｉｆｉｃｓｔｒｅｎｇｔｈｉｎＡｌＴＭＲＥ(ＴＭ=ｔｒａｎｓｉｔｉｏｎｍｅｔａｌ)ｓｙｓｔｅｍｓ.Ｔｈｅｙｈａｖｅｕｐｔｏ500～1100ＭＰａｉｎｓｔｒｅｎｇｔｈａｎｄｇｏｏｄｄｕｃｔｉｌｉｔｙ.Ｈｏｗｅｖｅｒ,ｔｈｅｏｒｉｇｉｎｏｆＡｌｂａｓ…     

Effect of Yttrium on Microstructures and Properties at Elevated Temperature of Mg-0.8Zr-0.35Zn Alloys

Asthelighteststructuralmetalmaterial ,themostobviousadvantagesofmagnesiumalloyaretheirhighspecificstrengthandspecificstiffness ,superdampingcapacityandmachinability ,excellentelectromagneticshieldingandnon toxicity .Theincreasingattentionhasbeenpaidonthepracticalapplicationofmagne siumalloysastheenergysavingandenvironmentpro tectionarebecomingtheworldfocus .However ,somedisadvantagessuchasignitableandcombustibledur ingmeltingandcastingandtheirrelativelypoorprop ertiesatelevatedtemperaturelimit…     

Amorphous forming ranges of Al-Fe-Nd-Zr system predicted by Miedema and geometrical models

A method based on the semi-empirical Miedema model and a geometrical model was used to study the glass forming abilities(GFA) and the amorphous forming ranges of Al-Fe-Nd-Zr system and its constituent ternary systems.The amorphous forming composition ranges were analyzed based on different criteria such as ΔGam-ss and PHSS(PHSS=ΔHchem(ΔSC/R)(ΔSσ/R)) for Al-Fe-Nd system.The predicted amorphous forming range was in good agreement with the experimental results.The results showed that the criterion of ΔGam-ss was more accurate,and agreed well with the experiment results.The Gibbs free energy difference ΔGam-ss and parameter PHSS were then used to predict the amorphous forming composition range for the rest of the constitutive ternary systems of Al-Fe-Nd-Zr.In addition,the amorphous forming composition ranges of the(Al-Fe-Zr)100–x Ndx(x=50,60,70) systems were predicted by ΔGam-ss and the modified parameter PHSS.The Gibbs free energy of Al10(Fe1–x Zrx)30Nd60 were also calculated.The GFA parameter PHSS indicated that the composition with the highest GFA was Al33.5Fe13.5Zr3Nd50 for the(Al-Fe-Zr)50Nd50 system,Al28.8Fe10Zr1.2Nd60for the(Al-Fe-Zr)40Nd60 system and Al22.8Fe6.9Zr0.3Nd70 for the(Al-Fe-Zr)30Nd70 system,and the results suggested that those alloys with high content of Al had higher GFA.The appropriate content of neodymium and zirconium resulted in the lower value of PHSS and increased the GFA obviously.