Anxian Lu

Luminescent properties of Tb3+ and Gd3+ ions doped aluminosilicate oxyfluoride glasses.

Tb(3+) and Gd(3+) ions doped lithium-barium-aluminosilicate oxyfluoride glasses have been prepared. The transmission, emission and excitation spectra were measured. It has been found that those Tb(3+)-doped lithium-barium-aluminosilicate oxyfluoride glasses exhibit good UV-excited luminescence. The luminescence intensity of Tb(3+) ion increases for those (Tb(3+), Gd(3+))-codoped glasses. Energy transfer process from Gd(3+) ion to Tb(3+) ion is indicated.

Structure and property of multicomponent germanate glass containing Y2O3

Abstract CaO–BaO–Al2O3–SiO2–GeO2 glasses doped with 0·00–16·67 wt-% Y2O3 have been prepared by conventional melt quenching method. The influence of Y2O3 addition on the properties and structure of the glasses has been investigated. The results show that, with the introducing of Y2O3, the density, glass transition temperature and thermal expansion coefficient of the glass increase but the chemical durability declines. In addition, compared with the glass without Y2O3, the bend strength of the glass including 4·76 wt-% Y2O3 increased from 54 to 110 Mpa. The possible mechanism is that yttria acts as a network former in the structure and makes the island shape network unit repolymerisation by forming Ge–O–Y bond. The absorption strength caused by hydroxyl vibration decreased up to completely disappearance as the Y2O3 content increased continuously. The introducing of yttria in the composition causes the conversion from four coordination to higher coordination germanium, which decreases non-bridge oxygen (NBO) and weakens hydroxyl characteristic absorption.

HIGHLY CRYSTALLINE TRANSPARENT GLASS CERAMICS: A CHALLENGING IMPORTANT RESEARCH DIRECTION

Crystal and transparent ceramics have been considered to be a new generation of materials with a very important role in secure and economic sustainable development. In this paper, the advantages and disadvantages among highly crystalline transparent glass ceramics, crystals, and ceramics have been compared, including their chemical composition, preparation technology, and the equipment requirement of the materials. Based on the authors knowledge and understanding, the possibility of highly crystalline transparent glass ceramics substituting for crystals or ceramics has been discussed. The present situation and newest progress in the research of highly crystalline transparent glass ceramics have been introduced. The attractive opportunities and difficult challenges in this research direction are shown in this article. In particular, this paper focuses on some ideas from the author, rather than a simple introduction to the existing situation and research progress of transparent materials.

Effect of K2O Addition on Crystallization and Microstructure of Li2O-ZnO-Al2O3-SiO2 System Glass-Ceramics

The Li2O-ZnO-Al2O3-SiO2 system glasses with varying content of K2O were prepared. Crystallization processes of these glasses were investigated using X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Microstructure of the glass-ceramics was studied using scanning electron microscopy (SEM). The sequence of crystallization of Li2O-ZnO-Al2O3-SiO2 glasses can be divided into three stages such as crystallization of β1-Li2ZnSiO4, crystallization of Li2Al2Si3O10 and conversion of β1-Li2ZnSiO4 to γ0-Li2ZnSiO4. The K2O content doesn’t vary the crystallization sequence but enhances the crystallization of β1-Li2ZnSiO4. At the same time the introducing of K2O in Li2O-ZnO-Al2O3-SiO2 system hinders the crystallization of Li2Al2Si3O10 and the transformation of β1-Li2ZnSiO4 to the more stable phase γ0- Li2ZnSiO4.

Research on Zr50Al15Ni10Cu25 bulk amorphous alloys prepared by mechanical alloying and low pressure sintering

Abstract Amorphous Zr50Al15Ni10Cu25 alloy powders were fabricated by mechanical alloying technique with commercially pure element powders. The effects of small amount of C, Si3N4 and SiC powders addition on the thermal stability and crystallisation behaviour of the Zr50Al15Ni10Cu25 amorphous alloy were investigated. The blended powders were compacted into bars by oil hydraulic press, and were sintered in argon atmosphere at different temperatures and pressures. The samples before and after sintering were characterised by X-ray diffraction, scanning electron microscopy, differential scanning calorimetry and electron tensile testing machine. The results demonstrated that a proper addition of Si3N4 powders to the amorphous matrix can improve the thermal stability of the matrix. Suitable additives can help to improve the density and mechanical properties of the matrix in sintering process.

Low electrical resistivity of a graphene–AgNHPs based ink with a new processing method

The purification and separation of nano-Ag particles is difficult because of the small size, it restricts the applications of nano-Ag. In this study, the AgNHPs solution was purified and separated with a membrane separation-centrifugation cleaning method, for use as the ink of printed electronics. Meanwhile, we prepared inkjet-printed patterns of conductive inks consisting of AgNHPs and graphene (GE) in different contents. It is found that high dispersity and low electrical resistivity of AgNHPs inks can be obtained by using membrane separation-centrifugation cleaning method. The AgNHPs particles show excellent dispersion and the electrical resistivity of the AgNHPs solution is 11.2 × 10−6 Ω cm at 150 °C, it increases the electrical conductivity of GE–AgNHP. It is also found that GE can significantly improve the electrical conductivity of the patterns when sintering is done at relatively low temperatures. When the GE content is 0.15 mg mL−1, the resistivity is the lowest. For instance, when sintering is done at 150 °C, the resistivity is 2.5 × 10−6 Ω cm that is 13% of that of the AgNHPs conductive ink; after sintering at 50 °C, this ratio is 2%. This study on GE–AgNHPs conductive inks sintered at low temperatures should further the development of flexible touch screens.

In situ synthesis and properties of self-reinforced \hbox {Si}_{3} \hbox {N}_{4}\textendash \hbox {SiO}_{2}\textendash \hbox {Al}_{2} \hbox {O}_{3}\textendash \hbox {Y}_{2}\hbox {O}_{3} \ (\hbox {La}_{2}\hbox {O}_{3}) glass–ceramic composites

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Phase transformation and microstructure of MgO–Al2O3–SiO2 system glass–ceramics under different heat treatment conditions

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