QCr0.5铬青铜熔炼工艺的改进

根据以往的生产经验，并通过多次反复试验，对QCr0．5铬青铜的传统熔炼工艺进行了改进。实际生产表明，采用新的熔炼工艺可显著降低生产成本，提高铸锭合格率。     

Fe-0.5Mn-0.5C预混合钢粉性能及粘结剂作用机制

设计4种不同有机粘结剂,分别对合金元素Mn、石墨进行粘结处理,制备Fe-0.5Mn-0.5C预混合钢粉。研究4种粘结剂对预混合钢粉合金元素与石墨的粘结率、预混合钢粉的流动性、松装密度、压坯密度的影响。并通过对粉末表面基团的表征,研究高分子粘结剂与铁基体间的相互作用方式。结果表明:以丙烯酸类树脂制备的预混合钢粉工艺性能最好,其流动速率为24.3 s/50 g松装密度为24.3 s/50 g,在600 MPa压力下的压坯密度为3.03~3.23 g/cm3粘结剂中的极性基团与铁基粉末通过氢键作用相吸附。     

Preparation and Electrical Transport Properties of Perovskite Oxide Ln0.5Sr0.5CoO3

The superfine powders of Ln0.5 Sr0.5 CoO3 （Ln = La, Pr, Nd, Sm, Eu） were obtained by solid state reactions. The crystal structure and electrical transport properties of samples doped with different rare earth elements as well as the forming process of the Perovskite structure were studied. The result shows that when the temperature reaches 1200 ℃, the samples will become a steady and unitary Perovskite phase by solid state reactions. The conductive behavor at low temperature is consistent with small polaron mechanism （i. e., localized electronic carriers having a thermally activated mobility）. However, the maximum of conductivity appears at about 700 ℃, and the conductivity of La0.5Sr0.5CoO3 is the biggest in the intermediate-temperature （600 - 850 ℃ ）, so it is fit for cathode material of intermediate-temperature solid oxide fuel cells.     

Growth and Spectral Properties of Crystal Er3+:Y0.5Gd0.5VO4

Er3 :Y0.5Gd0.5VO4 crystal with good optical quality was grown by Czochraski method. The structure of the crystal was determined by X-ray powder diffraction method. The segregation coefficient of Er3 ions in the crystal was measured by the ICP method. The absorption and emission spectra were also measured. On the basis of the spectra, the absorption cross-sections, emission spectrum FWHM and fluorescence lifetime of the crystal were calculated. From the properties mentioned above.     

Substituting Effect of Y in La0.5Ba0.5 CoO3

La0.5-xYxBa0.5CoO3 polycrystals were prepared by solid state reaction. The substituting effects of Y for La on the magnetic and transport properties of the materials were studied systematically. The results indicate that substitution of Y induces two effects. Firstly, the charge transfer from Y to 3d orbital of Co happens. This causes the molecular magnetic moment to decrease. Secondly, the antiferromagnetic exchange interaction of Co ions appears. When the content of Y is less than or equal to 30%, the non-colinear structure of spins in materials is observed. When the content of Y is greater than 30%, the materials transit from predominant ferromagnetic state to predominant antiferromagnetic one. The conductive mechanism for the materials with different content of Y belongs to the variable range hopping conduction of polarons.The resistivity of materials increases sharply with increasing Y content.     

Magnetic and Transport Properties of La0.5-x Ndx Ba0.5 CoO3 Compounds

Substituting effects of Nd for La in La0.5Ba0.5CoO3 compounds were studied systematically. The results show that Nd doping does not change the itinerant properties of the Co3d electrons. The molecular magnetic moment of the mate-rials decreases monotonically with increasing Nd dopant. When Nd content x ≥0.45, a magnetic phase separation appears in the materials. When x ≤0.45, the Curie temperature decreases monotonically with increasing Nd dopant. This is due to the size effects of the rare earth ions. The electric resistance measurements show that in the studied temperature range, the conduction of the materials belongs to the thermo-diffusion conduction below the Curie temperature, while it belongs to the variable range hopping conduction of polarons over the Curie temperature.     

0.5Li3VO4-0.5Li4TiO4的溶胶-凝胶法合成及其离子导电性

用非醇盐溶胶凝胶法合成了组成和粒度均匀的锂离子导体０．５Ｌｉ３ＶＯ４０．５Ｌｉ４ＴｉＯ４超细粒子。用Ｘ射线衍射、ＴＥＭ及交流阻抗等方法对产物进行了表征。产物中两相的相纯度各为５０％，粒径在０３μｍ以下，室温下的离子电导率为７１０×１０－６ｓ·ｃｍ－１。     

Preparation of Mesoporous Ce0.5Zr0.5O2 Mixed Oxide by Hydrothermal Templating Method

Mesoporous Ce0.5Zr0.5O2 mixed oxide with high specific surface area was synthesized under basic condition in the presence of non-ionic surfactant PEG-4000. The effect of synthesis conditions, such as synthesis temperature and the molar ratio of PEG-4000/（[ Ce] ＋ [ Zr] ）, on specific surface area were investigated. The products were characterized by transmission electron microscopy, powder X-ray diffraction, and nitrogen adsorption-desorption measurements, respectively. The results showed that synthesis temperature and the molar ratio of PEG-4000/（[ Ce] ＋ [ Zr] ） had great influence on specific surface area. Under the optimum synthesis conditions, the prepared Ce0.5Zr0.5O2 mixed oxide presented cubic fluorite-type structure and possessed high surface area of 148.6 m2·g^-1 with wormlike pores.     

Mg2 掺杂Zn0.5Cd0.5S固溶体光催化剂的制备及光解水制氢

采用水热法制备了Cd0.5Zn0.5S和掺杂0.4%(摩尔百分数)Mg2+的0.4%Mg/Cd0.5Zn0.5S固溶体光催化剂。采用UV-Vis、XRD以及电化学等手段对催化剂进行表征,并考查催化剂可见光下分解水制氢的活性。结果表明:Mg2+掺杂提高了Cd0.5Zn0.5S固溶体中光生电子和空穴的分离效率,大大提高了Cd0.5Zn0.5S固溶体光催化制氢的活性。     

Ni2+掺杂Cd0.5Zn0.5S固溶体制备及可见光分解水制氢研究

采用水热法制备了Cd0.5Zn0.5S和Ni2+掺杂Ni(m)/Cd0.5Zn0.5S固溶体光催化剂。通过XRD、UV-Vis漫反射光谱和电化学方法表征了催化剂的结构和光电性能，并考查了固溶体在以三乙醇胺为电子给体、可见光（λ≥420 nm）照射下光催化分解水制氢活性。结果表明，Ni2+掺杂后提高了催化剂对可见光的吸收，促进了光生电子—空穴的有效分离，有效提高了Cd0.5Zn0.5S固溶体的光催化制氢活性。当Ni2+的掺杂量为5%（摩尔百分数），反应体系NaOH浓度为0.5 mol/L时，催化剂活性最高，Ni(5)/Cd0.5Zn0.5S制氢活性为纯Cd0.5Zn0.5S固溶体的5倍。催化剂经15 h反应具有良好的稳定性。     

锂离子电池正极材料LixNi0.5Mn0.5O2电子结构的第一性原理研究

采用基于密度泛函理论的第一性原理超软贋势平面波法,对LixNi0.5Mn0.5O2的几何结构进行优化,并计算相应的电子结构和平均嵌锂电压.结果表明：x=1时,费米能级上分布着Ni、Mn d轨道电子和部分O2p轨道电子,层状LiNi0.5Mn0.5O2是电子的良导体;O2p轨道与Ni、Mn形成较强的共价键, Ni-O与Mn-O具有相近的键长,抑制了LiNiO2与m-LiMnO2中的因Jahn-Teller效应导致的八面体扭曲,且Mn-O键长在充放电过程中保持不变,材料具有稳定的结构;Li在晶胞中以主要离子态的形式存在,有利于脱嵌与传输.随着锂离子的脱出,材料的带隙增加,导电性能变差.     

快速热压制备(AgSbTe_2)_x(Pb_(0.5)Sn_(0.5)Te)_(1-x)半导体材料及热电性能研究

为了进一步提高PbTe系列合金的热电性能和降低生产成本,采用溶剂热反应合成平均粒度为500 nm的PbTe粉末,以所合成的PbTe粉末为主要原料通过封管熔炼法制备(AgSbTe2)x(Pb0.5SnvTe) 1-x(x=0,0.05,0.1,0.15,0.2)系合金.所得合金锭经过高能球磨制成微米级的超细合金粉,再通过快速热压烧结制备测试用的多晶试样,所有试样的相对密度均达到90%以上.通过XRD和SEM等手段分析材料的物相组成和微观结构,研究x的变化对于该体系材料热电性能(电阻率、Seebeck系数、热导率和ZT值)的影响.研究表明,当X取值为0.1时该体系材料的热电性能得到最优化,在575 K时取得最人的ZT值为1.093.     

钙钛矿锰氧化物Y0.5Ca0.5Mn0.8Fe0.2O3的电子顺磁共振研究

用固相反应法制备了Y0．5Ca0．5Mn0．8Fe0．2O3多晶陶瓷材料，借助电子顺磁共振技术对多晶样品在150—300K温度范围内的顺磁共振行为进行了研究。结果表明样品的顺磁共振线宽△Hpp和g因子的值随着温度的降低是增加的。线宽的增加是由于随着温度的降低，样品进入一个长程的反铁磁态，体系的铁磁关联增强导致的。g因子随温度的降低而增加表明体系的轨道有序是逐渐增强的。     

Preparation and mechanical properties of bulk ultrafine (W0.5Al0.5)C0.65 with minor Fe binder by reactive hot-pressing

Binderless (W_0.5Al_0.5)C_0.65 produced by reactive hot-pressing (RHP) has high hardness but low bending strength and fracture toughness. In this work, bulk ultrafine (W_0.5Al_0.5)C_0.65 with minor addition of Fe as the binder phase has been prepared by RHP. Rapid synthesis and high densification can be achieved for the (W_0.5Al_0.5)C_0.65 with 0.4–1.0?wt-%Fe by RHP at a relatively low temperature. Pure (W_0.5Al_0.5)C_0.65 without sub-carbide phase or brittle η-type phase can be synthesised due to the fact that the carbon vacancy in (W_0.5Al_0.5)C_y can reach 50%. And thanks to the combined effect of nanoscaled initial powders, low temperature, rapidly reactive sintering and pressure, bulk ultrafine (W_0.5Al_0.5)C_0.65-Fe with a grain size of about 0.2?μm can be obtained by RHP. Thus, with an appropriate amount of Fe (about 0.8?wt-% in this work), the bending strength and fracture toughness of (W_0.5Al_0.5)C_0.65 can be highly improved.     

容量型锂离子电池正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2的合成

采用共沉淀法合成Ni_(0.5)Co_(0.2)Mn_(0.3)(OH)_2前驱体,将前驱体和LiOH混合均匀后经高温煅烧合成了锂离子电池正极材料LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2,并对其进行电化学性能检测。试验表明,制备的电池在电压2.8～4.3V(vs.Li/Li+)区间内,0.1C倍率下的首次库伦效率为88.4%;在1C倍率下循环100次后,放电比容量为157.7mAh/g,容量保持率为96.6%。     

Al_3Ti_3CoCrCu_(0.5)FeMoNi高熵合金激光涂层的研究

使用激光熔覆制作了单相组成的Al_3Ti_3CoCrCu_(0.5)FeMoNi合金涂层,通过退火处理使基体相析出二元金属间化合物,使用SEM、XRD、显微硬度计分析了涂层的组织形貌、相结构和硬度。结果表明,激光熔覆制得的Al_3Ti_3CoCrCu_(0.5)FeMoNi涂层由BCC单相组成,显微硬度为905.2HV;在500℃以下退火处理,涂层的相组成不变。700℃以上退火,涂层从BCC相中析出二元金属间化合物Al_3Ti_3相,析出相随退火温度升高逐渐长大。涂层硬度随退火温度的升高先降低后逐渐升高,Al2Ti3相析出导致涂层硬度升高。经过900℃退火后,涂层硬度达到938.8HV,超过了未退火时涂覆态的硬度。     

LiNi_(0.5)Co_(0.2)Mn_(0.3)O_2的制备及其性能研究

采用二次高温煅烧法制备了三元复合正极材料LiNi0.5Co0.2Mn0.3O2,用SEM、XRD和蓝电测试仪等对其结构和物理化学性能进行表征和测定。结果表明,材料具有较好的层状结构,在2.75~4.25V下0.2C放电容量达到151mAh/g,经50次充放电循环后,放电容量仍为初始放电容量的93%,放电容量保持率较高,是一种电化学性能优良的三元正极复合材料。     

溶胶-凝胶自燃烧法合成镍铜锌纳米晶铁氧体及其吸波性能的研究

利用溶胶-凝胶自燃烧法合成了Ni0.25Cu0.25Zn0.5Fe2-xCexO4纳米晶铁氧体.借助DTA和XRD技术,对干凝胶的热分解过程、合成纳米晶的成分及其吸波性能进行了研究.结果表明,由金属硝酸盐和柠檬酸形成的干凝胶具有自燃烧的特性.通过自燃烧反应可以直接获得镍锌铜铁氧体粉末,经900℃热处理后可以转变成单一的尖晶石相,吸波性能测试发现,Ni0.25Cu0.25Zn0.5Fe2-xCexO4的吸波性能在8.2GHz～12.5GHz范围内随x的变化而不同,当x=0.07时,吸波性能最好,最高吸收峰值达到29.634dB.     

钛—硼和铝—硼处理对抗氢蚀1.25Cr—0.5Mo钢使用性能的影响

对Ａｌ－Ｂ或Ｔｉ－Ｂ处理的１．２５Ｃｒ－０．５Ｍｏ钢的研究结果表明：（１）Ａｌ－Ｂ和Ｔｉ－Ｂ处理明显增加了１．２５Ｃｒ－０．５Ｍｏ的淬透性，强度及塑、韧性；（２）Ａｌ－Ｂ和ＴｉＢ处理均使．２５Ｃｒ－０．５Ｍｏ钢的抗氧性能明显提高，当Ｂ含量相当时，Ｔｉ－Ｂ处理钢的抗氢蚀性能优于Ａｌ－Ｂ处理钢；（３）Ｂ含量较高时，钢的抗氧蚀性能较强，但塑、声望生及回火性能却相对较差，因此，较低含量Ｂ处理更有利于材料综     

热处理对0.14C-1.25Cr-0.5Mo钢的抗氢蚀能力的影响

试验研究了经不同温度正火和回火后，0．14C—1．25Cr—0．5Mo钢中M3C、M23C6碳化物中Cr、Mn、Mo的含量以及充氢前后淬火和回火温度对钢的力学性能的影响。结果得出，经890-980℃正火、670-710℃回火，该钢具有良好的抗氢蚀能力，520～620℃回火后试样充氢后的强度明显下降。