爆炸固结加自蔓延高温合成Ti／Al2O3梯度功能材料

采用爆炸固结加自蔓延高温合成（ＳＨＳ）法制备了Ｔｉ／Ａｌ２Ｏ３梯度功能材料（ＦＧＭ），并对所制备的ＦＧＭ的成分、组织和性能进行了研究。实验结果表明，采用该法可制备成分、组织和性能呈梯度分布、且符合设计要求的致密ＦＧＭ。此外还研究了Ｔｉ／Ａｌ２Ｏ３ＦＧＭ合成过程中的反应模式     

Synthesis and crystal structure of an organic-inorganic complex [Cu(DMF)3(H2O)2]2[SiMo12O40]·2H2O

The synthesis and crystal structure of an polyoxometalate-based organic-inorganic complex [Cu(DMF)3(H2O)2]2[SiMo12O40]·2H2O (DMF = N, N-dimethyl formamide) is described in this article. It was characterized using elemental analysis, thermal analysis, infrared, ultraviolet, and electron spin resonance spectroscopic studies. The X-ray crystallography analysis showed that the copper centers are pentacoordinated to show the square pyramidal geometry, and the polyanion [SiMo12O40]4- which is semi-coordinated to the copper(Ⅱ) centers prevents the existence of a sixth ligand. In addition, the intracationic hydrogen interaction enhanced the stability of the copper coordination cation.     

Synthesis and crystal structure of an organic-inorganic complex [Cu（DMF）3（H2O）2]2[SiMo12O40]·2H2O

The synthesis and crystal smacture of an polyoxometalate-based organic-inorganic complex [Cu（DMF）3（H2O）212[SiMo12O40].2H2O （DMF = N, N-dimethyl formamide） is described in this article. It was characterized using elemental analysis, thermal analysis, infrared, ultraviolet, and electron spin resonance spectroscopic studies. The X-ray crystallography analysis showed that the copper centers are pentacoordinated to show the square pyramidal geometry, and the polyanion [SiMo12O40]4- which is semi-coordinated to the copper（I/） centers prevents the existence of a sixth ligand. In addition, the intracationic hydrogen interaction enhanced the stability of the copper coordination cation.     

铝热还原氮化法制备TiN-Al2O3复合粉体

本文用Al作还原剂还原氮化TiO2制备了TiN—Al2O3复合粉体。通过对比不同温度下的含氮率和理论含氮率，可以判断反应进行的程度；通过XRD分析研究不同温度下的相变化；通过SEM、EDS分析观察晶粒的形貌和成分。研究结果发现，TiN在1100℃开始生成，1450℃TiN生成反应结束。SEM照片显示细小、不规则的TiN晶粒和多面体Al2O3晶粒相互交叉均匀分布，Al2O3晶粒尺寸10μm左右，TiN晶粒尺寸2μa左右。表明用此方法可以在比较低的温度下合成颗粒细小分散均匀的TiN-Al2O3复合粉体。     

燃烧合成—热压制备Al2O3—TiC—ZrO2纳米复合隐瓷的力学性能与显微结构

以TiO2,Al,C,纳米ZrO2粒子为原料,利用燃烧合成-热压工艺制备了Al2O3-TiC-ZrO2纳米复合陶瓷.添加ZrO2可使Al2O3-TiC断裂方式由沿晶断裂转变为穿晶断裂.ZrO2纳米粒子弥散于基体中,其周围产生的应力集中可引发位错,起到亚晶界的作用,并可使位错钉扎、堆积,阻碍位错运动,从而使复合陶瓷的力学性能得到明显改善抗弯强度为706 MPa,提高幅度达19.8%;断裂韧性为6.3 MPa@m1/2,提高幅度18.9%;洛氏硬度为94.4.     

Thermoelectric properties of p-type (Bi,Sb)2Te3 alloys fabricated by the hot pressing method

P-type (Bi_0.25Sb_0.75)₂Te₃ powders were fabricated by melting/grinding and mechanical alloying processes. Thermoelectric properties of the hot-pressed (Bi_0.25Sb_0.75)₂Te₃ were characterized with the powder processing method, powder size, hot pressing temperature, and the amount of excess-Te dopant. Specimens fabricated by melting/grinding exhibited lower Seebeck coefficient, lower electrical resistivity and higher thermal conductivity, compared to the specimens prepared by mechanical alloying. 3 wt.% excess Te-doped (Bi_0.25Sb_0.75)₂ Te₃, fabricated by melting/grinding and hot pressing at 550°C, exhibited a figure-merit of 3.2 x 10^-3/K. For 1 wt.% excess Te-doped specimen prepared by mechanical alloying and hot pressing at 550°C, a figure-merit of 3.05 x 10^-3/K was obtained.     

Microstructural Observations on 1:2 ordered domain boundaries in Ba(Mg1/3Ta2/3)O3

High resolution transmission electron microscopy (HRTEM) has been used to investigate the detailed microstructures of the antiphase boundaries (APBs) of 1:2 B-site ordered domsins in fully ordered Ba(Mg_1/3Ta_2/3)O₃ ceramic compound. The orientation relationship (102)_I // (012)_II, [010]_I // [100]_II was found between two domains. The ledged coherent interface has formed with (101) plane as an atomic habit plane. The growth ledge which possesses the kinks on ledge structure on the riser has the height of 1.22 nm which is equivalent to three (101) planes. The coalescence of the growth ledges and the genera~ion of these ledges at the structurally faulted region had been found experimentally. New interface model which was coherent and had a growth ledge was constructed based on the experimentally obtained diffraction pattern and HRTEM images and thereafter the lateral growth by the ledge mechanism in the coarsening of ordered phase boundaries was proposed.     

MICROSTRUCTURES AND MECHANICAL PROPERTIES OF IN-SITU Al2O3/TiAl COMPOSITES BY EXOTHERMIC DISPERSION METHOD

In-situ Al2O3/TiAl composites were fabricated by pressure-assisted exothermic disper-sion (PAXD) method from elemental powder mixtures of Ti, Al, TiO2, and Nb2O5.The microstructures and mechanical properties of the as-sintered composites are in-vestigated. The results show that the as-sintered products consist of γ-TiAl, α2-Ti3Al,Al2O3, and NbAl3 phases. Microstrueture analysis indicates that Al2O3 particles tend to disperse on the grain boundaries. Application of a moderate pressure of 35 Mpa at 1200℃ yields Ab2O3/TiAl composites with fine Al2O3 reinforcement and a dis-continuous network linking by Al2O3 particles. The aluminide component has a fine submicron γ+α2 larnellar rnicrostructure. With increasing Nb2O5 content, A1203 par-ticles are dispersed uniformly in the matrix. The hardness of the composites increases gradually, and the bending strength and fracture toughness of the composites reach to the maximum value, respectively.     

退火温度对Fe72.5Cu1Nb2V2Si13.5B9软磁合金微结构的影响

用Ｘ射线射,透射电子显微镜,数字图像分析等实验技术,系统研究了快淬制制备的Ｆｅ７２．５Ｃｕ１Ｎｂ２Ｖ２Ｓｉ１３．５Ｂ９非晶条带经５００－７５０℃０．５ｈ退火后合金的相组成,晶格参数和晶粒尺寸随温度的变化规律。结果表明,在５３０－５４５℃,退火０．５ｈ,电子数字定量金相测量得到的α－Ｆｅ纳米固溶相平均晶粒尺寸为１３．７－１４．９ｎｍ,当退火温度高于５６０℃时,晶粒体大速度显著磁特性。 时,α－Ｆｅ（     

Cis-[Pt(NH_3)_2(H_2O)_2](NO_3)_2与1,1-环丁烷二羧酸钠形成的一种新的Pt(Ⅱ)配合物(英文)

从Cis-[Pt(NH3)2(H2O)2](NO3)2 与1,1-环丁烷二羧酸钠的化学反应中,分离出一种新的Pt(II)配合物,通过元素分析、红外光谱, 质谱和高效液相色谱的分析测试,初步推测结构为顺式-四氨-μ-二(1,1-环丁烷二羧酸根-O1,O2)合二铂的新化学结构式.     

Thermodynamics of Cu(Ⅱ)-NH3-NH4Cl-H2O system

The thermodynamics of a complex solution system, Cu(Ⅱ)-NH3-NH4Cl-H2O, was presented both theoretically and experimentally. Firstly, according to the principles of simultaneous equilibrium and aqueous electronic charge neutrality of the system, a nonlinear mathematical thermodynamic model with multi-members was set up. In this model, there were six unknowns: pH value, concentration values of free Cl-, free NH3, total concentration values of Cu2 , Cl- and NH3, four equilibrium equations and three equilibrium equations of total quantum of Cu2 , Cl- and NH3, as well as an equilibrium equation of electric charge, were involved in the model. Then after specifying the values of total concentrate of NH3 and Cl-, the model was solved precisely using MATLAB language, and the other four unknowns were obtained. According to the values obtained above, various valuable figures regarding thermodynamic relation of the system were protracted also with MATLAB, including two and three dimensions figures. These figures and data can supply the theoretic conference for optimizing the ratio of leaching reagents in copper extraction through ammonia hydrometallurgy. Finally, the solubility of CuO were measured in the system of NH3-NH4Cl-H2O. The results show that the model and the thermodynamic data obtained are reliable.     

Preparation of basic nickel carbonate particles in solution system of Ni( Ⅱ )-NH3-CO2-3-H2O

Based on the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Ni( Ⅱ )-NH3-CO2-3-H2O system at ambient temperature were deduced theoretically and the thermodynamic diagrams of lg[Ni]T versus pH at different solution compositions were drawn, which was quite effective to explain the formation mechanism of precipitation particles with different microscopic shapes. When pH of the solution is below 7.0, free nickel ions are dominant and when the precipitant is added, the fast coagulation will take place leading to the loose flocculation particles. While pH is above 7.0, because of the coordination of nickelion with ammonia, the precipitation proceeds slowly accompanying with the release of Ni2 from the multi-coordinated Ni(NH3)2 n (n= 1, 2, …, 6), which easily leads to the formation of the dense spherical particles.     

微波辐射Mg(OH)2制备轻质活性MgO新工艺

探讨了微波辐射Mg(OH)2制备轻质活性MgO的可行性，研究了微波功率、微波辐射时间、物料重量对Mg(OH)2分解率的影响，得到了微波辐射Mg(OH)2制备轻质活性MgO的最佳工艺：微波功率800W，微波辐射时间8分钟．物料重量4克，其煅烧时间只有传统方法的1／10，Mg(OH)2分解率为99．62％，氧化镁含量95．09％，碘吸附值为78．68mg／g，产品指标达到了沪Q/HGll-238-82一极标准。     

复合体材料CuFe2O4-Pb(Mg1/3Nb2/3)O3的内耗和介电损耗

用传统的固相反应方法制备了CuFe2O4-Pb(Mg1／3Nb2／3)O3复合体材料陶瓷,用X射线衍射确定了复合体材料中各相的存在．用双端振动簧法研究了样品在-200—400℃的音频内耗谱,在37．6℃发现一个很大的内耗峰P1,并伴随着约9％的模量的软化,表明了相变的存在．在室温下,测量了介电常数ε′和介电损耗tanδ随频率变化的关系;同时,测量了复合体材料的介电常数和介电损耗随温度的变化关系,进一步验证P1峰由立方到四方的相变引起．最后给出样品的磁滞回线。     

PSZ(3Y)含量对Al2O3陶瓷力学性能的影响

对部分稳定ZrO2(简称PSZ(3Y))含量与Al2O3基陶瓷烧结致密化及力学性能的关系进行了测试,用X射线衍射定量相分析计算了m-ZrO2和t-ZrO2相在断裂前后相含量的变化.结果表明当Al2O3中添加15%(体积分数)PSZ(3Y)时,1550℃真空烧结后Al2O3基复合陶瓷的抗弯强度达到884 MPa,断裂韧性达到8.2 MPa@m1/2.PSZ(3Y)的相变增韧提高了 Al2O3/PSZ(3Y)复合陶瓷材料的抗弯强度和断裂韧性.     

气－固相反应法制备Sm_2Fe_（17）N_y永磁合金过程中氮原子的扩散

研究了氮原子在Ｓｍ_２Ｆｅ_（１７）合金中的扩散行为，测定了扩散温度、时间与样品平均氮含量的关系，以及氮原子在样品中的分布；计算了氮原子在Ｓｍ_２Ｆｅ_（１７）合金中的扩散频率因子Ｄ_０和扩散激活能Ｑ，运用扩散Ｆｉｃｋ第二定律计算了氮原子在Ｓｍ_２Ｆｅ_（１７）粉末颗粒内部的分布及其与扩散温度、扩散时间、颗粒尺寸之间的关系．理论计算与实验结果一致．     

AlN/SiC_w(Y_2O_3SiO_2)复合材料热处理增强机理

利用ＸＲＤ, ＥＰＭＡ 和ＨＲＥＭ 等测试技术对ＡｌＮ／ＳｉＣｗ（Ｙ２Ｏ３ＳｉＯ２） 复合材料热处理增强机理进行了研究。结果表明： 材料在１ ３００ ℃空气中进行热处理, 其氧化处理过程也是其热处理增强过程, 增强机理主要是由于氧化扩散改变了粒界玻璃相的相组成, 粒界玻璃相在高温氧化气氛下和ＡｌＮ颗粒发生作用, 生成ＡｌＮ 多形体２ＨδＳｉａｌｏｎ 相, 并与ＳｉＣ 晶须形成空间交错的结构     

（Y，Gd）2O3：Eu^3＋纳米粒子制备及光谱特性

用湿化学共沉淀法制备了(Y,Gd)2O3:Eu3 纳米粒子.用XRD,TEM,SEM及差示/热重分析(DSC/TG)手段对粉体进行了表征.用荧光光度计分析了样品的激发光谱和发射光谱.结果表明:在煅烧温度为800℃保温2 h时,合成出近似球形、粒径均匀且分散性好的(Y,Gd)2O3:Eu3 纳米粒子,一次颗粒尺寸约为20 nm.样品在波长为612.0 nm监控光下激发,出现235和250 nm两个激发峰,分别为(Y,Gd)2O3基质吸收和Eu3 迁移态(CTS)吸收造成的.两个波长激发下的发射光谱峰强度前者高于后者.当掺杂Eu3 的摩尔浓度为3%时,发射光谱对应5D0→7F2能级跃迁的相对峰强度最大,当Eu3 掺杂的摩尔浓度为7%时,相对峰强度反而降低,这是由于Eu3 的浓度猝灭造成的.     

弛豫铁电体Pb(Mg1/3Nb2/3)O3-PbTiO3的相变

测量了(1-x％)镁铌酸铅-x％钛酸铅(1≤X≤11)(简称PMNTx)陶瓷样品的介电常数、内耗和Young’s模量．观测到在Tm温度附近,即在介电常数达到最大值时,出现一个内耗峰,并且模量发生软化．这反映了极化纳米微畴的弛豫．对于PMNTx(5≤x≤11)的样品,在Tm温度以下的某个温度出现附加的内耗峰和Young’s模量的异常,表明样品中发生了自发的弛豫铁电到铁电(简称R-F)的相变,对R-F相变的机制进行了讨论．     

Low-field magnetoresistance of (1-x)La_(0.6)Dy_(0.1)Sr_(0.3)MnO_3/0.5x (Sb_2O_3) composite system under different sintering temperatures of matrix

A series of (1-x)La0.6Dy0.1Sr0.3MnO3/0.5x(Sb2O3)(x=0.15) samples were prepared by the solid-state reaction method, and the influence of sintering temperature of the matrix on low-field magnetoresistance of (1-x)La0.6Dy0.1Sr0.3MnO3/0.5x (Sb2O3) was studied through the measurements of X-ray diffraction (XRD) patterns, scanning electron microscope (SEM) image, resistivity-temperature (ρ-T) curves, and magnetoresistance-temperature (MR-T) curves. The results indicate that for the samples with low sintering temp...