Thermal and chemical methods for producing zinc silicate (willemite): A review

Takesue, Masafumi; Hayashi, Hiromichi; Smith, Richard L.

doi:10.1016/j.pcrysgrow.2009.09.001

Cited by 182 publications

(74 citation statements)

References 199 publications

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“…In the Zn 2 SiO 4 crystal, Mn 2+ occupies part of the Zn 2+ sites, which are coordinated by four oxygen atoms. 53,54 The weak crystal eld around Mn 2+ results in a low splitting width of its 3d energy levels. The position of the luminescence band maximum is then inuenced by the coordination environment.…”

Section: 52mentioning

confidence: 99%

Synthesis and evaluation of a PVDF–PT3MA–Zn2SiO4:Mn hybrid polymeric composite for optical device applications

et al. 2014

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A new hybrid organic/inorganic composite consisting of poly(3-thiophene methyl acetate) (PT3MA), poly(vinylidene fluoride) (PVDF) and manganese-doped zinc silicate (Zn 2 SiO 4 :Mn) has been synthesized and applied for the fabrication of an optical device. Recrystallized PVDF was used as a host matrix for the PT3MA polymer and Zn 2 SiO 4 :Mn inorganic compound. The active layer was deposited on an indium-tinoxide (ITO)-coated glass substrate by the drop casting technique. A spin-coating method was also used for morphological comparison purposes. The synthesized material as well as the device (aluminium electrodes/PVDF-PT3MA-Zn 2 SiO 4 :Mn/ITO/glass) was characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), dark current-voltage (I-V) characteristic curves, absorbance and photoluminescence (PL) spectroscopy. The results show spherical-and irregular-shaped microparticles both dispersed on and within the PVDF matrix, which correspond to PT3MA and Zn 2 SiO 4 :Mn, respectively. The hybrid composite shows strong luminescence at z525 nm superimposed by a broadband between 600 and 800 nm, originating from the Zn 2 SiO 4 :Mn radiative transitions and from the recombination of photogenerated carriers at PT3MA. At room temperature, the device presented semiconductor behaviour typically observed for photodetectors and a DC electrical conductivity of z0.37 mS cm À1.

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Section: 52mentioning

confidence: 99%

Synthesis and evaluation of a PVDF–PT3MA–Zn2SiO4:Mn hybrid polymeric composite for optical device applications

et al. 2014

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“…Synthetic Mn-doped willemite is widely applied as a phosphor in neon discharge lamps, fluorescent lamps, oscilloscopes, black-and-white/color televisions and many other displays and lighting devices since 1930s (Takesue et al 2009). Zn 2 SiO 4 is also a member of the M 2 SiO 4 (M: divalent cations, for example, Mg, Fe, Co and Ni) group that includes the most important constituent minerals of the Earth's mantle.…”

Section: Introductionmentioning

confidence: 99%

Crystal structures of Zn2SiO4 III and IV synthesized at 6.5–8 GPa and 1,273 K

2013

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We report the crystal structures determined under ambient condition for two Zn 2 SiO 4 polymorphs synthesized at 6.5 GPa and 1,273 K (phase III) and 8 GPa and 1,273 K (phase IV) and also compare their 29 Si MAS NMR spectroscopic characteristics with those of other Zn 2 SiO 4 polymorphs (phases I, II and V). Electron microprobe analysis revealed that both of phases III and IV are stoichiometric like the lower-pressure polymorphs (phases I and II), contrary to previous report. The crystal structures were solved using an ab initio structure determination technique from synchrotron powder X-ray diffraction data utilizing local structural information from 29 Si MAS NMR as constraints and were further refined with the Rietveld technique. Phase III is orthorhombic (Pnma) with a = 10.2897(5), b = 6.6711(3), c = 5.0691(2) Å . It is isostructural with the high-temperature (Zn 1.1 Li 0.6 Si 0.3 )-SiO 4 phase and may be regarded as a 'tetrahedral olivine' type that resembles the 'octahedral olivine' structure in the (approximately hexagonally close packed) oxygen arrangement and tetrahedral Si positions, but has Zn in tetrahedral, rather than octahedral coordination. Phase IV is orthorhombic (Pbca) with a = 10.9179(4), b = 9.6728(4), c = 6.1184(2) Å . It also consists of tetrahedrally coordinated Zn and Si and features unique edge-shared Zn 2 O 6 dimers. The volumes per formula under ambient condition for phases III and IV are both somewhat larger than that of the lower-pressure polymorph, phase II, suggesting that the two phases may have undergone structural changes during temperature quench and/or pressure release.

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“…It was confirmed by the results XRD analysis, which no registered presence of calcium oxide at these temperatures. Takesue [18] reported that willemite phase begins to form by solid diffusion of ZnO on the surface of SiO 2 as we can observe on the SEM micrograph (Fig. 2a).…”

Section: Discussionmentioning

confidence: 56%

Characteristic of synthesis and transformations of hardystonite in willemite glass-crystalline glaze based on thermal analysis

Gasek

Partyka

Gajek

et al. 2016

J Therm Anal Calorim

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A new crystalline phase hardystonite (Ca 2 ZnSi 2 O 7 ) has been obtained in willemite glass-ceramic glaze containing more than 20 % by mass ZnO. To our knowledge, there was no report about the presence of this calcium zinc silicate in glazes. The aim of this study was to investigate the synthesis and thermal behavior of Ca 2 ZnSi 2 O 7 in ceramic glaze. A hardystonite formed in glaze at 750°C and exist to 850°C, as confirmed by X-ray phase powder diffraction findings and scanning electron microscope image (SEM) with chemical elemental analysis. The second formed of zinc calcium silicate is corresponding with liquid phase presence in glaze observed at 1150°C and also decompose below 1200°C. Because glaze is complicated multi-component system with different crystalline phases, it is developed for research transformations in stoichiometric hardystonite. On this basis, an oxide system was prepared from SiO2, ZnO and CaCO 3 to designated precise chemical synthesis temperature of pure hardystonite powders. Thermal analysis method such as differential scanning calorimetry has confirmed that in 1175°C formed hardystonite according to X-ray phase powder diffraction of a reaction mixture. Hot-stage microscope is useful to detailed description of the processes and transformations which occur when mixture and glaze were heated. SEMs of the new phase in mixture and in glaze are presented. Phenomena related with the influence of heating cycle and liquid phase on the transformation of hardystonite are examined and analytically discussed.

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Thermal and chemical methods for producing zinc silicate (willemite): A review

Cited by 182 publications

References 199 publications

Synthesis and evaluation of a PVDF–PT3MA–Zn2SiO4:Mn hybrid polymeric composite for optical device applications

Synthesis and evaluation of a PVDF–PT3MA–Zn2SiO4:Mn hybrid polymeric composite for optical device applications

Crystal structures of Zn2SiO4 III and IV synthesized at 6.5–8 GPa and 1,273 K

Characteristic of synthesis and transformations of hardystonite in willemite glass-crystalline glaze based on thermal analysis

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