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Superficial Physical Property and Functionalization of SiO2 Particles

Author: WangLeiYan
Tutor: ZhengZhiXiang
School: Hefei University of Technology
Course: Materials Science
Keywords: Spheroidization Hydrothermal Synthesis Photoluminescence Mn2 doped Zn2SiO4 Particles of SiO2
CLC: TB383.1
Type: Master's thesis
Year: 2010
Downloads: 85
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Abstract


SiO2 because of its good chemical and thermal stability, and has been widely used in industrial production, either directly used to produce a key component in the fiber optic crystal photonics technology can also be made via reduction various semiconductor components used in a variety of electronic technology, automatic control technology and measurement techniques. After refinement of pink quartz, silica powder, silica micron or even nano-SiO2 in the field of rubber reinforcement, UV shielding, electronic packaging materials chemical widely used. IC packaging filler material microsilica with the rapid development of the information industry showed broad prospects for development, Today, large-scale VLSI packaging materials are increasingly high, especially for particle shape the spheroidization requirements, so further study of spherical particles of SiO2, will have broad application prospects. Further, the particles of SiO2 surface Functional cladding, it has a corresponding light emitting, coloring and other features will further expand the scope of its application, while the silicate matrix of light-emitting material has a good chemical and thermal stability, has long been widespread concern, will occupy a very important position in the field of light-emitting material. This thesis consists of particles of SiO2 shaping and coated with SiO2 surface light-emitting material in two parts: 1) chemical method as well as a combination of chemical and mechanical methods to achieve the spherical shape of the particles of SiO2, and under different temperature, concentration and time Plastic particles SiO2 were studied, experimental results show that, purely chemical methods is at a temperature of 220 ° C, the KOH concentration of 2.5%, the top shaping effect of the reactive of 24h particles of SiO2, this time part of the corners becomes smooth, and further by high KOH concentration, particle SiO2 will be cracking and then display the new sharp edges and corners, the shaping effect of the pure chemical particles SiO2; particles SiO2 milling 3h processing in different concentrations of KOH so he tried, the effect is excellent in the previous method. 2) by the hydrothermal synthesis method in particle SiO2 surface coated Mn2 doped Zn2SiO4 (adding KOH or dilute ammonia), and the cladding layer structure, morphology, and different temperatures, the heat treatment atmosphere material photoluminescence performance research, and Zn2SiO4 the reaction mechanism of the crystal in the hydrothermal reaction process were discussed. The XRD results show that under hydrothermal conditions 220 ° C, add a small amount of KOH reaction at different times, generated at the surface of the quartz sand layer of Zn2SiO4 SEM photos show the generated Zn2SiO4 hexagonal prism, and under different reaction conditions Zn2SiO4 coated with different degrees. Mn2 doped nano Zn2SiO4 coated SiO2 samples are shown in the two sets of photoluminescence spectra, a 250nm excitation around 522nm green luminescence band, another set of 340-410nm band excitation 440nm blue emission band, the former is typical the Mn2 ion luminescence, the latter 440nm emission band may have originated in the matrix SiO2. Using ammonia as a catalyst, 220 ° C reaction at different times, has not been heat-treated samples produced only 520nm green emission peak luminous intensity of heat-treated after no significant changes, but the samples showed a broadband emission of 470nm ~ 520nm; while in 120 ° C, and at different temperatures of 160 ° C and 180 ° C for reaction for 6 days, the sample showed blue emission peak of 470nm, while the reaction for 6 days at 200 ° C and 220 ℃ samples also shows the 520nm green light emission peak luminescence intensity, after heat treatment No significantly enhanced, but shows a broadband region of 470nm ~ 520nm.

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