用化学气相沉积(CVD)法制备硫化锌(ZnS)体块材料中晶体缺陷和生长工艺的研究

本文报道了用化学气相沉积 (CVD)法制备高质量红外光学体块材料硫化锌 (ZnS)的制备工艺 ,研究了晶体缺陷对其光学性能的影响。XRD ,XEM及IR表明 ,采用优化的沉积工艺和热等静压后处理 ,减少晶体中杂质、微孔、六方结构ZnS及Zn H键的形成 ,使生长的CVDZnS具有高的红外透过率 。

光学超晶格:从体块到薄膜

光学超晶格是一种基于准相位匹配技术的非线性光学材料。通过铁电畴工程研制出不同微结构的光学超晶格,可以实现高效灵活的非线性频率转换,并对光场进行多维调控。光学超晶格的基质材料,经历了从体块到薄膜的发展,伴随着两种材料体系超晶格制备技术的突破,催生了激光变频技术、非线性光场调控和多功能集成光量子芯片等重要应用。

Enhanced plasticity of Fe-based bulk metallic glass by tailoring microstructure

The room temperature compressive plasticity of Fe75MosP10Cs.3B1.7 bulk metallic glass （BMG） was improved from 0.5% to 1.8% by increasing the sample diameter from 1.5 mm to 2.0 mm. With increasing the sample diameter to 2.0 mm, a heterogeneous microstructure with in-situ formed a-Fe dendrite sparsely distributed in the amorphous matrix can be attained. This heterogeneous mierostructure is conceived to be highly responsible for the enhanced global plasticity in this marginal Fe-based BMG.

Effect of minor Nb addition on mechanical properties of in-situ Cu-based bulk metallic glass composite

In-situ formed （Cu0.6Zr0.3Ti0.1）95Nb5 bulk metallic glass （BMG） composite with Nb-rich dendrite randomly dispersed in hard glassy matrix was prepared by casting into a water-cooled copper mold. The dendrite has much smaller hardness and elastic modulus than glassy matrix, and the stress concentration at interface provides a channel for the initiating and branching of shear bands upon loading, thus leading to a high compressive fracture strain of 6.08% and fracture strength about 2200 MPa. Comparing with other Cu-based BMG composite, the fracture strength of present （Cu0.6Zr0.3Ti0.1）95Nb5 composite is not significantly reduced, indicating that the addition of Nb in the current work is an effective and effortless way to fabricate new practical BMG composites with enhanced strength and good plasticity.

Effect of melt infiltration parameters on microstructure and mechanical properties of tungsten wire reinforced(Cu_(50)Zn_(43)Al_(7))_(99.5)Si_(0.5) metallic glass matrix composite

Using melt infiltration casting at different temperatures （965, 990 and 1015 °C） for different time （10 and 15 min）, the composites of （Cu50Zr43Al7）99.5Si0.5 bulk metallic glass reinforced with tungsten wires were produced. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and quasi-static compression tests were carried out to evaluate the microstructure and mechanical properties. The results show that the maximum ultimate compressive strength and strain-to-failure of about 1880 MPa and 16.7% were achieved, respectively, at the infiltration temperature of 965 °C for 15 min.

Effects of infiltration parameters on mechanical and microstructural properties of tungsten wire reinforced Cu_(47)Ti_(33)Zr_(11)Ni_6Sn_2Si_1 metallic glass matrix composites

Cu47Ti33Zr11Ni6Sn2Si1-based bulk metallic glass matrix composites reinforced with tungsten wires were fabricated by infiltration process at different temperatures （850, 900, 950 and 1000 °C） and time （10, 20 and 30 min） in a quartz or a steel tube. The mechanical tests were carried out by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the maximum strength and total strain of the composite are 1778 MPa and 2.8% fabricated in steel tube at 900 °C for 10 min, and 1582 MPa and 3.6% fabricated in quartz tube at 850 °C for 10 min, respectively.

Strategies for designing metal oxide nanostructures

There has been exponential growth in research activities on nanomaterials and nanotechnology for appli- cations in emerging technologies and sustainable energy in the past decade. The properties of nanomaterials have been found to vary in terms of their shapes, sizes, and number of nanoscale dimensions, which have also further boosted the performance of nanomaterial-based electronic, catalytic, and sustainable energy conversion and storage devices. This reveals the importance and, indeed, the linchpin role of nanomaterial synthesis for current nanotechnology and high-performance functional devices. In this review, we provide an overview of the synthesis strategies for design- ing metal oxide nanomaterials in zero-dimensional （0D）, one-dimensional （1D）, two-dimensional （2D）, and three-di- mensional （3D） forms, particularly of the selected typical metal oxides TiO2, SnO2 and ZnO. The pros and cons of the typical synthetic methods and experimental protocols are reviewed and outlined. This comprehensive review gives a broad overview of the synthetic strategies for designing ＂property-on-demand＂ metal oxide nanostructures to fur- ther advance current nanoscience and nanotechnology.

Bio-inspired multifunctional metallic glass

As a novel class of metallic materials, bulk metallic glasses(BMGs) have attracted a great deal of attention owing to their technological promise for practical engineering applications. In nature, biological materials exhibit inherent multifunctional integration, which provides some inspiration for scientists and engineers to construct multifunctional artificial materials. In this contribution, inspired by superhydrophobic self-cleaning lotus leaves, multifunctional bulk metallic glasses(BMG) materials have been fabricated through the thermoplastic forming-based process followed by the SiO_2/soot deposition. To mimic the microscale papillae of the lotus leaf, the BMG micropillar with a hemispherical top was first fabricated using micro-patterned silicon templates based on thermoplastic forming. The deposited randomly distributed SiO_2/soot nanostructures covered on BMG micropillars are similar to the branch-like nanostructures on papillae of the lotus leaf. Micro-nanoscale hierarchical structures endow BMG replica with superhydrophobicity, a low adhesion towards water, and self-cleaning, similar to the natural lotus leaf. Furthermore, on the basis of the observation of the morphology of BMG replica in the Si mould, the formation mechanism of BMG replica was proposed in this work. The BMG materials with multifunction integration would extend their practical engineering applications and we expect this method could be widely adopted for the fabrication of other multifunctional BMG surfaces.