固溶时效对铸造Ti-6Al-2Sn-2Zr-2Cr-2Mo-2Nb钛合金组织和性能的影响

研究了固溶时效制度对铸造Ti-6Al-2Sn-2Zr-2Cr-2Mo-2Nb钛合金组织及力学性能的影响。结果表明,适当的热处理制度可以明显提高合金的室温及高温强度,但是塑性略有下降。Ti-6Al-2Sn-2Zr-2Cr-2Mo-2Nb铸造钛合金组织以集束状的片状α相为主,热处理后α集束的尺寸得到细化。采用915℃×2 h+空冷+590℃×4 h+空冷的热处理制度可以得到较理想的显微组织和良好的室温及高温综合力学性能。     

硬脂酸法制备TiO2-SnO2纳米粉

采用硬脂酸法分别制备了SnO2纳米粉体及TiO2-SnO2混合纳米粉,并应用XRD和TEM等分析方法对所得粉体进行了表征.结果显示,采用硬脂酸法制备了粒径约18nm的SnO2纳米粉体和粒径约5-15nm的TiO2-SnO2纳米粉体.     

Si_2N_2O-Al_2O_3-La_2O_3和Si_2N_2O-Al_2O_3-CaO系统的亚固相关系

本文给出了 Si_2N_2O-Al_2O_3-La_2O_3和 Si_2N_2O-Al_2O_3-CaO 系统的亚固相图。实验结果表明:在 Si_2N_2O-Al_2O_3-CaO 系统中有一个未知结构的新化合物 CaO·Si_2N_2O,在3CaO·Si_2N_2O 和3CaO·Al_2O_3两化合物之间形成连续立方固溶体。而 Si_2N_2O-Al_2O_3-La_2O_3系统中则没有发现新化合物。在两个系统的富 Si_2N_2O区,过量的 Si_2N_2O 与 La_2O_3和 CaO 分别反应形成 Si_3N_4与 La_(10)[SiO_4]_(?)N_2(H-相)(和 CaSiO_3。所研究的这两个三元系统中,分别形成了如下几个四元相容性区。在 Si_2N_2O-Al_2O_3-La_2O_3系统内有:H-Si_3N_4-La_2O_3·Si_2N_2O-La_2O_3·Al_2O_3;H-Si_3N_4-La_2O_3·Al_2O_3-La_2O_3·11 Al_2O_3;H-Si_3N_4-La_2O_3·11 Al_2O_3-Al_2O_3;H-Si_3N_4-Al_2O_3-O′s.s;H-Si_3N_4-O′s.s-Si_2N_2O在 Si_2N_2O-Al_2O_3-CaO 系统内有:Si_3N_4-CaSiO_3-CaO·Si_2N_2O-3CaO·Al_2O_3;Si_3N_3-CaSiO_3-3CaO·Al_2O_3-2CaO·Al_2O_3·SiO_(?);Si_(?)N_(?)-CaSiO_3-2CaO·Al_2O_3·SiO_2-Al_2O_3;Si_3N_4-CaSiO_3-Al_2O_(?)-O′s.s;Si_3N_4-CaSiO_3-O′s.s-Si_(?)N_(?)O     

Ti(acac)2Cl2/AlEt2Cl(或AlEt2Cl-ZnCl2)催化剂催化丙烯腈聚合反应

研究了Ti(acac)2Cl2／AlEt2Cl催化丙烯腈聚合反应,分析了加入第三组分ZnCl2对聚合反应的影响,用^13C—NMR对聚合产物进行了表征,并探讨了聚合反应机理。结果表明,随着聚合温度的提高和聚合反应时间的增加,单体转化率增大,聚丙烯腈的分子量提高。当体系中n(AN)／n(Cat)超过一定量时,则得不到高聚物。体系中加入ZnCl2能明显提高单体转化率和产物分子量,并且产物的三单元规整结构含量明显增加。     

Ti/SnO_2 Sb_2O_3 MnO_2/PbO_2阳极的性能研究

制备了一种非贵金属阳极－Ｔｉ／ＳｎＯ２＋Ｓｂ２Ｏ３＋ＭｎＯ２／ＰｂＯ２,并用ＸＲＤ、ＳＥＭ进行了表征,计算出了电极的分形维数,测定了该电极在硫酸中的使用寿命和动力学参数,把该电极用于处理含酚废水和Ｐｂ电极进行对比．结果表明,节电３３％,转化率达９５％,是一种优良的电化学催化剂．     

NaAlO2含量对ZAISil2Cu2Mgl铝合金Na2SiO3微弧氧化陶瓷膜性能的影响

为了进一步探明添加剂种类及含量对ZAlSil2Cu2Mgl铝合金微弧氧化陶瓷膜性能的影响,在Na2SiO,电解液中,添加不同浓度的NaAlO2进行了微弧氧化,利用能谱仪（EDS）分析了陶瓷膜表面元素含量,用扫描电镜（SEM）观察其表面形貌,以x射线衍射仪（XRD）分析了膜的相组成,并测试了膜的厚度、硬度和极化曲线;研究了NaALO2添加量对微弧氧化陶瓷膜特性的影响。结果表明,随着NaAlO2添加量的增加,陶瓷膜表面微孔尺寸变小,表面Al,O元素含量下降;起弧电压和最终氧化电压下降;陶瓷膜厚度增加,硬度和耐蚀性先提高后下降;陶瓷膜的相组成改变不明显。NaALO2添加量为1g／L时陶瓷膜的综合性能最好。     

Gd2O2S-HoCu2复合磁性蓄冷材料的制备研究

采用粉末冶金方法首次制备了Gd2O2S-HoCu2金属-陶瓷复合性蓄冷材料。结果表明，将Gd2O2S与HoCu2两种磁性蓄冷材料粉末按照一定比例混合，经球磨处理后压制成块，在氩气保护气氛下1100℃保温30min进行真空烧结，可制备成Gd2O2S-HoCu2金属-陶瓷复合磁性蓄冷材料，新型的金属-陶瓷复合磁性蓄冷材料由GOS与HoCu2两相构成，其比热性能良好，作为3～10K温区附近的蓄冷材料使用非常具有实用价值。     

SiCp-WSi2/MoSi2复合材料的室温力学性能

为了提高MoSi2的室温断裂韧性,将Si、Mo、W和C四种粉末混合后通过"原位反应热压"一次热压工艺制备了两种不同体积配比的SiCp-WSi2/MoSi2复合材料试样,测定了复合材料试样和纯MoSi2试样的室温.断裂韧性(KIC)与显微硬度(HV);采用X射线衍射(XRD)、扫描电镜(SEM)等方法研究了该工艺下试样的结构、组织以及断口形貌与断裂韧性问的相互关系.结果表明,SiC的复合化和W元素的合金化能使SiCp-WSi2/MoSi2复合材料晶粒细化,硬度、室温断裂韧性比纯MoSi2明显提高,断裂韧性最高值达5.88 MPa·m1/2.并对复合材料的硬化、韧化机理分别进行了分析.     

MgO-Al2O3-SiO2-TiO2-Y2O3玻璃的弹性模量

根据硬盘基板用材料的要求,制备了MgO-A12Oa-SiO2-TiO2-Y2Oa高弹性模量玻璃(120GPa).玻璃的弹性模量随组成的变化服从Makishima-Mackenzie理论,MgO、A12O3、TiO2、Y2O3等具有较高单位体积离解能的氧化物有利于提高玻璃的弹性模量.但玻璃弹性模量的理论计算值低于测试值.这是因为Makishima-Mackenzie理论没有考虑玻璃内阳离子的具体配位状态,对MgO、Y2O3堆积密度因子的推导存在误差.因此利用Makishima-Mackenzie理论发展高弹性模量玻璃时应对MgO、Y2O3等氧化物的计算进行修正.     

等离子喷涂Al_2O_3-TiO_2-ZrO_2涂层及其耐磨损性能

采用液相喷雾造粒法将准微米Al_2O_3,TiO_2,纳米ZrO2颗粒团聚成微米粉体,并用等离子喷涂技术制备了含纳米颗粒的Al_2O_3-TiO_2-ZrO_2陶瓷涂层.在MM200型环块磨损试验机上进行了常温干摩擦试验,比较了含有纳米颗粒的Al_2O_3-TiO_2-ZrO_2涂层和传统Al_2O_3-TiO_2陶瓷涂层的耐磨损性能,并用扫描电镜观察磨损后的磨痕形貌.结果表明,含有纳米颗粒的涂层耐磨损性能明显优于传统的陶瓷涂层.     

Superconductivity of barium-doped Bi2Sr2CaCu2Oy

Sintered ceramic samples of Bi₂Sr_2–x Ba _x CaCu₂O_y with nominal barium fraction 0x0.3 have been prepared by the solid-state reaction method. WDS studies verified that barium enters the superconducting phase. For slowly cooled samples, the midpointT _c of the superconducting transition is significantly increased by barium doping, whereas for quenched samplesT _c is little affected. The increase ofT _c with increasing barium fraction is consistent with a decrease in the hole concentration in the superconducting layers.     

Comparison of the Electronic Structures of La2CuO4, Sr2CuO2Cl2, and Sr2CuO2F2

First-principles cluster calculations are reported of the local electronic structure of the three compounds: La₂CuO₄, Sr₂CuO₂Cl₂, and Sr₂CuO₂F₂. The copper and the planar oxygen 2p atomic orbitals exhibit a similar degree of covalency. The out-of-plane orbitals, however, are quite different with the atomic orbital lowered significantly in energy for chlorine and fluorine apical positions.     

Selective solar-driven CO2 reduction mediated by 2D/2D Bi2O2SiO3/MXene nanosheets heterojunction

Photocatalytic CO₂ reduction reaction (CO₂RR) is an environment-friendly technique for clean fuel generation.Developing low-cost and efficient photocatalyst/cocatalyst systems for boosting CO₂ RR is still a challenge.Herein,a novel Bi₂O₂SiO₃/Ti₃C₂2D/2D heterojunction photocatalysts are successfully prepared by in situ growth of Bi₂O₂SiO₃ on the surface of ultrathin Ti₃     

Reactivity of the H2O2/TiO2 system

The reactivity of the H₂O₂/TiO₂ system for samples treated at atmospheric pressure is studied by means of Auger Electron Spectroscopy. The most significant changes on the TiO₂ ‘final’ state are: (i) The I(O)/I(Ti) peak-to-peak ratio is diminished by 15%. (ii) The LMV transition suffers an energy shift of +2 eV, whereas the peak-to-peak width diminishes 1.5 eV. (iii) Its structure changes with respect to that of the TiO₂ ‘initial’ state although it is not identified with any one of the known stoichiometric oxides. (iv) When the samples that represent the ‘final’ state are heated up to 650 K, the AES spectrum matches quite well that of the TiO₂ ‘initial’ state.     

Quasiparticle dispersion of Sr2CuO2Cl2

Recent angle resolved photoemission (ARPES) measurements for the insulating cuprate Sr₂CuO₂Cl₂ have provided the first experimental data which can be directly compared to the (theoretically) well-studied problem of a single hole propagating in an antiferromagnet. Some discrepancies withthe familiar 2D t— J model were observed. Here we discuss a comparison between the ARPES results and the quasiparticle dispersion of both (i) the extended t— t— J Hamiltonian and (ii) the three-band Hubbard model.     

MgO-Al2O3-SiO2-TiO2-Y2O3玻璃的弹性模量

根据硬盘基板用材料的要求，制备了MgO-Al2O3-SiO2-TiO2-Y2O3高弹性模量玻璃（120GPa)，玻璃的弹性模量随组成的变化服从Makishima-Mackenzie理论，MgO,Al2O3,TiO2,Y2O3等具有较高单位体积离解能的氧化物有利于提高玻璃的弹性模量，但玻璃弹性模量的理论计算值低于测试值，这是因为Makishima-Mackenzie理论没有考虑玻璃内阳离子的具体配位，对MgO,Y2O3堆积密度因子的堆导存在误差，因此利用Makishima-Mackenzie理论发展高弹性模量玻璃时应对MgO,Y2O3等氧化物的计算进行修正。     

Les phases SrLa2Al2O7 et SrGd2Al2O7

SrLa₂Al₂O₇ and SrGd₂Al₂O₇ belong to the structural type Sr₃Ti₂O₇. In SrGd₂Al₂O₇ strontium and gadolinium occupy respectively the 12 and 9 coordinated sites, whereas in SrLa₂Al₂O₇ the homologous cations are statistically distributed. The fluorescence spectra of both phases activated by Eu³⁺ ions show that the only possible position of Eu³⁺ is the 9 coordinated site.     

Ti/SnO2+Sb2O3+MnO2/PbO2阳极的性能研究

制备了一种非贵金属阳极－Ｔi/SnO2 Sb2O3 MnO2/PbO2,并用ＸＲＤ、ＳＥＭ进行了表征,计算出了电极的分形维数,测定了该电极在硫酸中的使用寿命和动力学参数,把该电极用于处理含酚废水和Ｐb电极进行对,结果表明,节电３３％,转化率达９５％,是一种优良的电化学催化剂。     

Na2O-B2O3-SiO2-SnO2系统的分相与析晶

对Na2O-B2O3-SiO2-SnO2四元系统的分相与析晶进行了探讨．通过对不同组成点在热处理、化学处理各阶段的试样进行能谱分析、XRD分析及SEM分析，确认了SnO2分布在分相结构中的富硼碱相中；在该系统中SnO2晶体的析出有赖于分相过程；分相结构尺度限制了SnO2的析晶尺寸．试验结果表明，通过控制分相结构得到了负载于多孔富硅载体的纳米尺寸的SnO2材料．该材料具有较高的CO氧化催化活性．     

Natural and persistent superhydrophilicity of SiO2/TiO2 and TiO2/SiO2 bi-layer films

Sol-gel SiO₂/TiO₂ and TiO₂/SiO₂ bi-layer films have been deposited from a polymeric SiO₂ solution and either a polymeric TiO₂ mother solution (MS) or a derived TiO₂ crystalline suspension (CS). The chemical and structural properties of MS and CS bi-layer films heat-treated at 500 °C have been investigated by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscospy. Water contact angle measurements show that MS SiO₂/TiO₂ and CS TiO₂/SiO₂ bi-layer films exhibit a natural superhydrophilicity, but cannot maintain a zero contact angle for a long time over film aging. In contrast, CS SiO₂/TiO₂ bi-layer films exhibit a natural, persistent, and regenerable superhydrophilicity without the need of UV light. Superhydrophilic properties of bi-layer films are discussed with respect to the nature of the TiO₂ single-layer component and arrangement of the bi-layer structure, i.e. TiO₂ underlayer or overlayer.