P型Sr0．5Co4-xFexSb12化合物的制备及高温热电性能

采用熔融法结合放电等离子烧结（SPS）技术合成了P型填充方钴矿化合物Sr0．5Co4-xFexSb12，并研究了Fe掺杂对该化合物高温热电性能的影响。采用X．射线衍射（XRD）及电子探针（EPMA）表征了化合物的物相及化学成分，在300～850K温度范围内测试了化合物的电导率、赛贝克系数和热导率，采用Vande Pauw方法测试了化合物的室温载流子浓度。实验结果表明，化合物的主要相组成为Sr0．5Co4-xFexSb12方钴矿相，同时含有少量FeSb2和CoSb2杂质相。化合物的赛贝克系数均为正值，表明为空穴导电。随着Fe掺杂量的增加，化合物的载流子浓度及电导率增加，赛贝克系数降低，晶格热导率降低，最小室温晶格热导率为1．97 Wm^-1K^-2。对于化合物Sr0．5Co2.32Fe1.68Sb12在850K时获得的最大热电性能指数ZT约为0．60。     

Fe掺杂对Bi2Sr2Co2Oy热电性能和自旋关联的影响

采用固相合成法制备出系列Fe掺杂的Bi2Sr2Co2Oy，样品，并对样品进行XRD分析，电阻率（p）、热电势（固和顺磁共振研究。结果表明：Fe掺杂浓度x≤0．3时样品基本为单相。Fe掺杂使体系的电阻率略微增大，热电势显著升高，这可能与Fe掺杂降低了空穴载流子浓度有关。Fe掺杂浓度x=0．05样品获得最大的功率因子（power factor，S^2／P）。顺磁共振结果显示，不掺Fe的样品有着较强的顺磁共振（ESR）信号，随着Fe含量的增加，ESR信号向低频方向移动，并逐渐宽化减弱直至消失。这表明Fe掺杂改变了体系的自旋关联状态，占据了Co位参与了Co—O—Co之间的自旋关联。研究结果表明合适的元素掺杂可以有效地调整体系的自旋关联状态，改善材料的热电性能。     

β-FeSi2基热电材料的研究进展

介绍了β-FeSi2合金的基本特性和制备方法。评述了目前通过不同的元素掺杂可制得N型或P型β-FeSi2基半导体材料以及在热电性能方面取得的重要大进展。其中掺杂Co,B元素可得到N型β-FeSi2基半导体材料,且掺杂Co,在850K最大ZT值为0.4;而掺杂B,高于800K时Z值是未掺杂3￣6倍,在667K最大Z值为1.18×10-4K-1。掺杂Mn,Cu,Al可获得P型β-FeSi2基半导体材料,掺杂Mn在873K时最大Z值达2×10-4K-1;掺杂Cu可缩短β相的生成时间;掺杂Al,在743K获得的最大Z值为1.55×10-4K-1。指出通过结构优化、组分调整,进一步提高β-FeSi2基合金的热电性能。     

Co对Ni-Mn-Sn系哈斯勒热电合金组织与性能的影响

基于Heusler型合金的各项优异性能,运用机械球磨、真空熔炼以及热处理工艺制备了Co元素掺杂的Ni_(50-x)Co_xMn_(39)Sn_(11)(x=0,2,4,6)系Heusler型系列块体材料。采用光学显微镜,能谱仪对块体试样进行组织结构的表征,利用激光导热仪、热电参数测试系统测试试样的热电性能,研究了不同温度条件下掺杂Co元素对Ni基Heusler型合金材料的组织结构及热电性能的影响规律。结果表明:适量的Co掺杂,可以改善材料的热电性能,使得电导率随掺杂量的增加而增大。掺杂后试样的热电优值升高,且x=6试样在700K获得最大热电优值。     

Fe—Sm—Si热电合金的电学特性

采用悬浮熔炼法制备了Fe-Sm-Si热电合金材料,并研究了其电学输运特性。实验表明:在Fe1-xSmxSi2合金中,Sm为n型掺杂元素,Sm轻掺杂时,试样仍为p型,随着Sm量的增加,试样的Seebeck系数和功率因子都降低;Sm含量x 0.4的高Sm硅化物试样为n型,其中,热电性能最好的试样成分为Fe0.6Sm0.4Si2,其电阻率在10-5W穖数量级,而Seebeck系数仍达到80 mV稫-1左右。其机理被认为是由于Sm的4f层电子的贡献。     

Ag^＋掺杂Na0．5K0．5NbO3无铅压电陶瓷的无压烧结及性能研究

铅基压电陶瓷在制备、使用及废弃处理过程中都会造成环境污染，随着环保意识的增强，无铅压电陶瓷必将逐步替代铅基压电陶瓷。Na0．5K0．5NbO3是一种很有潜力的无铅压电陶瓷，掺杂各种元素提升Na0．5K0．5NbO3陶瓷的压电性能成为当今研究热点之一。本研究以Ag2O、Na2CO3、K2CO3、Nb2O5为原料，经750℃焙烧分别合成了Na0．5K0.5NbO3和AgNbO3粉料，再经配料、混料与成型，在1060℃埋粉烧结，制备出Ag^＋掺杂的Na0.5K0．5NbO3无铅压电陶瓷（xAgNbO3-（1-x）Na0.5K0．5NbO3，ANKN），并在较宽成分范围内（Ag^＋含量，x=0-50at％）系统研究了Ag^＋掺杂对ANKN陶瓷性能的影响。XRD结果表明，ANKN陶瓷的主相为钙钛矿型结构，当x〉16at％，开始出现K5-75Nb10．85O30杂相，随着Ag掺杂量的增加，杂相的衍射峰增强。电学性能测试结果表明，当x〈20at％，随Ag掺杂量的增加ANKN陶瓷的压电常数、介电常数等略有升高；当x〉20at％，ANKN陶瓷的各项性能均开始降低；Ag掺加量为x=16at％时ANKN陶瓷性能最佳，压电常数d33达到110pC／N，平面机电耦合系数kp为30％，相对介电常数εr为358，居里温度Tc为300℃。     

专利信息摘编

热冲击性能优异的复合轧辊[德国] DE19827861，1999．01．07，T．Kanno，Mitsubishi Materials Co．（日本）本专利的耐冲击复合轧辊由外部和内部等两层组成，外部由烧结碳化钨组成，主要成分为：w（Co）8％-27％，w（Ni）2％。12％，w（Cr0．3％。3．0％。内部为冶金结合的球墨铸铁，其主要成分为：w（C）3％-4．5％，w（Si）1．5％-4．5％，w（Mn）0．1％-2．0％，w（Mg）0．02％。0．2％，余下为Fe，球墨铸铁中还可含有Mo、Cu、Cr、V、W、Sn和Sb等元素。     

一种廉价的高性能稀土磁体

利用Sin。Co；，金属问化合物的2－17型稀土磁体，包括有Sin（Co、Fe、Cu）。s和Sin（Co、Fe、Cu、Zr）。。两种磁体，具有3OMG0e以上的最大磁能积和10k0e以上的矫顽力。但稀土Srn的价格昂贵，资源短缺，迫切希望利用资源丰富的Nd、Ce、Pr未取代一部分Sin，开发较廉价的高性能稀土磁体。因此，日本爱知钢公司开发了如下成分的2-17型稀土磁体，含（wt％）Sins～20，Nd、Pr、Y之中至少任选1种6～20，Fe10～25，Cu5～10，Zr和／或Hf1～4，Mn0．1～1，Ti0．1～1，P和／或S0．003～0．015，并且Sin＋Nd＋Pr＋Y保持在22～28范围以内…     

P型Yb_yFe_xCo_(4-x)Sb_(12)化合物的制备及热电性能

采用熔融法制备了P型填充式方钴矿化合物Yb_yFe_xCo_(4-x)Sb_(12),并研究了Co位Fe掺杂对该化合物热电传输特性的影响.在300～850 K的温度范围内,测试了化合物的电导率、赛贝克系数和热导率.结果表明,化合物的主要相组成为Yb_yFe_xCo_(4-x)Sb_(12),EPMA结果显示化合物中含有微量FeSb_2和CoSb_2杂质相.化合物的赛贝克系数均为正值,表明为p型半导体.随着Fe掺杂量的增加,化合物的电导率增加,晶格热导率降低,最小室温晶格热导率仅为1.33 W·m~(-1)K~(-1),对于化合物Yb_0.29Fe_1.2Co_2.8Sb_(12),在800 K时获得最大热电优值ZT约为0.67.     

Sb掺杂对Mg_2Si基化合物热电性能的影响(英文)

采用感应熔炼和真空热压的方法制备了Sb掺杂和未掺杂的Mg2Si基热电材料.研究了Sb掺杂对Mg2Si基热电材料的结构以及热电特性的影响.结果表明:通过Sb掺杂使得载流子浓度从3.07x1019 cm-3增加到1.25x1020 cm-3,电子有效质量也相应增加.测试了从室温到800 K下试样的Seebeck系数,电导率和热导率.结果显示,0.3 at%Sb掺杂使得电导率得到显著增加,在783 K时,ZT值达到0.7.     

Co对重掺Sm的FeSi2基热电材料电学性能的影响

用悬浮熔炼法制备了含Sm和Co的N型FeSi2 基热电材料 ,研究了Co对含Sm的FeSi2 材料电学性能的影响。结果表明 ,材料的电学性能是由两种掺杂元素共同决定的 :Sm能明显降低样品的电阻率 ,而适量的Co能提高重掺Sm的FeSi2 基热电材料的α值和功率因子 ,Co在含Sm的FeSi2 中的最佳掺杂摩尔分数为 2 .2 3%左右。     

V-Ti-Cr-Fe合金的储氢性能研究

研究了V（30％）-Ti（15％～55％）-Cr（7％～43％）-Fe（2％～18％）（原子分数，下同）四元合金的储氢性能。结果表明：V-Ti-Cr-Fe四元合金的吸氢量与有效吸氢量主要由Ti／（Cr＋Fe）比决定，当Ti／（Cr＋Fe）=1时，合金具有最好的吸放氢性能。随着Ti／（Cr＋Fe）比升高，合金的晶格常数增大，氢化物的生成焓增大，放氢平台压力降低。在298K时，V30Ti35Cr25Fe10合金的吸氢量达到3．6％（质量分数，下同），有效吸氢量达到2．0％。     

沉积态(Fe88Zr7B5)0.97Cu0.03软磁合金薄膜的磁性和巨磁阻抗效应

采用射频溅射法在单晶硅衬底上制备了(Fe88Zr7B5）0．97Cu0．03非晶软磁合金薄膜样品，对沉积态样品的软磁性能和巨磁阻抗(GMI)效应进行了实验研究与机理分析．结果表明，未掺Cu元素的Fe88Zr7B5沉积态合金薄膜几乎无GMI效应，而掺了适量Cu元素的(Fe88Zr7B5)0．97Cu0．03合金薄膜在沉积态下即具有显著的GMI效应．在13MHz频率下，最大纵向磁阻抗比达17％，最大横向磁阻抗比为11％，这表明(Fe88Zr7B5)0．97Cu0.03非晶合金薄膜在沉积态已具备优异的软磁性能和巨磁阻抗效应．同时讨论了该薄膜样品的巨磁阻抗效应随频率的变化特性．     

A study of structural, optical and magnetic properties of Zn0.97−xCuxCr0.03O diluted magnetic semiconductors

A set of Zn_0.97−xCu_xCr_0.03O (0 ≤ x ≤ 0.03) samples has been synthesized by the sol-gel method. The structural, optical and magnetic properties of the samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and vibrating sample magnetometer (VSM). With Cu doping concentration increasing up to 2 at%, the XRD results showed that all diffraction peaks corresponded to wurtzite structure of ZnO, but for Zn_0.94Cu_0.03Cr_0.03O, the secondary phase of Cu emerged. PL measurements showed that Zn_0.97−xCu_xCr_0.03O powders and pure ZnO with the Cu concentration varied from 0.00 to 0.02 exhibited obvious blue shift; the green emission peak could be effectively enhanced with the increase of the Cu concentration. Magnetic measurements indicated that room-temperature ferromagnetism of Zn_0.97−xCu_xCr_0.03O was an intrinsic property when Cu concentration was less than 0.02. The saturation magnetization of Zn_0.97−xCu_xCr_0.03O (x = 0, 0.01, 0.02) increased with the increase of the Cu concentration.     

β-phase transformation and thermoelectric power in FeSi2 and Fe2Si5 based alloys containing small amounts of Cu

The effects of Cu addition on the β phase formation rate and the thermoelectric power in various FeSi₂ and Fe₂Si₅ based alloys was examined. The peritectoid reaction (a+→β) in FeSi₂ alloys was initially enhanced by the addition of Cu but it became slower for longer annealing times. The retained metallic ε was harmful for the thermoelectric power. The inherent thermoelectric properties of (FeSi₂)_99−XMn₁Cu_X (X=0–1.O at.%), (FeSi₂)_99−X Co₁Cu_X (X=0–1.0 at.%) alloys were attained after the elimination of ε. In the case of eutectoid reaction (→β+Si). Differential thermal analysis, X-ray diffraction and microscopic observation clearly confirmed that the eutectoid reaction rate was drastically enhanced by the addition of a small amount of Cu and its rate decreased with decreasing Cu content. The rate also depends on the annealing temperature and reached a maximum at about 1073 K for most alloys. The addition of only 0.1 at.% Cu was still very effective even in Mn or Co doped alloys. The thermoelectric power of these alloys increased very quickly with annealing time. Their final values decreased with Cu content and saturated at 0.2 at.% Cu. The value of the 0.1 at.% Cu added alloy was higher than that of both the conventional p- and a-type FeSi₂ based alloys. These results suggest that the Fe₂Si₅ alloys with a small amount of Cu may be attractive as new thermoelectric materials.     

Effect of Fe on Microstructure and Coercivity of SmCo-Based MagnetsEI北大核心CSCD

High-temperature permanent magnets have an important application in the aerospace and other high-tech fields, among which 2:17-type SmCo magnets have become the first choice for high-temperature permanent magnets due to the strong magnetic anisotropy and high Curie temperature. Although there are studies on the effect of Fe on the remanence and coercivity, the role that Fe plays on coercivity mechanism of SmCo magnets is still unclear. In this work, Sm(CobalFexCu0.08-0.10Zr0.03-0.033) z (x= 0.10-0.16, z=6.90 and 7.40) magnets are prepared and the magnetic properties under different temperatures are investigated. The magnets with an intrinsic coercivity of 603.99 kA/m and a maximum energy product of 87.30 kJ/m(3) at 500 degrees C. are obtained. It is revealed that at room temperature the coercivity of the magnets increases with increasing Fe content, however, at 500 degrees C. the coercivity shows an opposite dependency on Fe content. Moreover, the effect of Fe on coercivity is more obvious at low z value. The phase structure and composition analyses were characterized by XRD and TEM. The results show that with the increase of Fe content, the size of the 2: 17R cell phase increases, the volume ratio of cell boundary 1: 5H phase decreases, and furthermore, both Fe content in the 2: 17R phase and Cu content in the 1: 5H phase increase. The variations of Fe and Cu contents in both phases lead to the change of the domain wall energy difference. With the increase of Cu content of 1:5H phase, the domain wall energy of 1: 5H phase (gamma(1:6)) drops faster at room temperature, the coercivity is determined by gamma(2:17)-gamma(1:5), so the coercivity increases with increasing Fe content. While at 500 degrees C, due to gamma(1:6) at its Curie temperature, the coercivity is mainly determined by the domain wall energy of 2: 17R phase (gamma(1:17)), which decreases with increasing Fe content. The increase of Fe content at the low z value results in a smaller growth of cell size, which leads to a more significant change in coercivity.     

Thermoelectric performance of polycrystalline Sn1-xCuxSe (x = 0–0.03) prepared by high pressure method

P-type Sn_1-xCu_xSe (x = 0–0.03) polycrystal was prepared through melting synthesis and high pressure (6.0 GPa) sintering (HPS) method. The composition and microstructure of the samples was analyzed, and the thermoelectric transport properties were investigated in the temperature range of 303 K–823 K. The results indicate that the electrical conductivity increases as Cu content increases. An observable improvement is found for the Seebeck coefficient when x is 0.01. In addition, the total thermal conductivities (κ_tot) of all samples decrease with rising temperature, and reach its minimum values at 773 K. As a result, the maximum power factor (PF) and ZT_max value are 378 μW m⁻¹ K⁻² and 0.79 for Sn_0.97Cu_0.03Se at 823 K, respectively.     

Structure and magnetic properties ofhigh-performanced Sm2（Co, Fe, Cu, Zr）17 alloys

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｈｉｇｈＣｕｒｉｅｔｅｍｐｅｒａｔｕｒｅａｎｄｌｏｗｅｓｔｔｅｍｐｅｒａ ｔｕｒｅｃｏｅｆｆｉｃｉｅｎｔｏｆｔｈｅＳｍ2 Ｃｏ17ｐｅｒｍａｎｅｎｔｍａｇｎｅｔｓｍａｋｅｔｈｅｍｂｅｉｄｅａｌｃａｎｄｉｄａｔｅｓｆｏｒｈｉｇｈｔ     

Characterization of the martensitic transformation in Ni50−xTi50Cux alloys through pure thermal measurements

The addition of a third element to the Ni-Ti system often changes the product and the path of the martensitic transformation of the alloy, which is a direct B2-B19′ transformation for the NiTi alloy in the fully annealed state. In this study we investigate the martensitic transformation of fully annealed Ni_50−xTi₅₀Cu_x (x = 3-10 at%) shape memory alloy (SMA) samples using differential scanning calorimetry (DSC) and the four-probe electrical resistance (ER) measurements under stress-free conditions. DSC and ER data show that the ternary alloy goes through a direct B2-B19′ transformation for Cu content between 3 and 7 at% and through the two-stage B2-B19-B19′ transformation for Cu content between 8 and 10 at%. We find good agreement between the two techniques as regards the detection of the phase transformation temperatures. B19′ starting and finishing temperatures decreases with the increases of Cu content and show a significant reduction starting from 7 at%; the range of temperatures in which B19 is stable increases with increasing Cu content.     

The pitting corrosion of sputtered Fe base alloy films

Predominantly single phase Fe base alloy films were prepared by a DC sputtering method. The compositions of the alloy films, as determined by Auger electron spectroscopy (AES) were Fe-7 at% Cr and Fe-18 at% Cr, Fe-11 at% W and Fe-19 at% W, Fe-9, −13 and −27 at% Ta. The pitting potential of the sputtered alloys determined in chloride solutions was found to be strongly dependent on the nature and the concentration of the alloying element. The pitting potential of sputtered Fe-18 at% Cr and Fe-27 at% Ta alloy films were approximately 0.9 V higher than that of bulk Fe and 0.6 V higher than that of Fe-19 at% W alloy film. A very good correlation was found between the pitting potential of Fe alloy films and the solubility of an alloying element oxide in acidic solutions with a pH corresponding to that within the stable pits of pure Fe (pH = 2). The pitting potential of the Fe alloy was found to increase with a decrease in the solubility of the alloying element oxide in acidic solutions. The pitting potentials of the sputtered Fe-7 at% Cr and Fe-18 at% Cr alloy films were were significantly higher than those of the bulk materials with the same composition. The higher pitting potentials of these alloy films are tentatively attributed to the presence of very fine particles of the oxide phase that are homogeneously distributed in the sputtered alloys.