scholarly journals Synthesis of Zirconia Micro-Nanoflakes with Highly Exposed (001) Facets and Their Crystal Growth

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 871
Author(s):  
Haibo Yan ◽  
Jian Di ◽  
Jiahao Li ◽  
Zhuoyu Liu ◽  
Junfeng Liu ◽  
...  

This study reports a novel preparation method of zirconia micro-nanoflakes with high (001) facets that is generated through a hydrolysis reaction of the fluozirconic acid (H2ZrF6). Zirconia micro-nanoflakes synthesized at varied conditions were analyzed by the SEM, EDS, μ-XRD, and Raman spectroscopy to characterize the morphology and probe into the crystal growth mechanism. The synthesized zirconia crystals in the form of elliptical micro-nanoflakes or irregular nanoflakes generally display the highly exposed (001) facets with a thickness of 1–100 nm and a length of 0.1–2.0 μm. As the temperature and initial solution concentration increased, the particle sizes of the synthesized zirconia micro-nanoflakes became more uniform and the thicknesses of the (001) facets became larger, suggesting that the synthesized zirconia crystals grow along the (001) facets and mostly along the c-axis direction. This is confirmed by the data from the μ-XRD patterns. The results also demonstrate that an oriented attachment-based growth occurring in a fluorine-rich solution environment was involved in the aggregation and coarsening of zirconia micro-nanoflakes. Meanwhile, synthesized zirconia micro-nanoflakes also evolved from a mixture of monoclinic and tetragonal systems to a pure monoclinic system (i.e., baddeleyite) with the temperature increasing, suggesting a key role of temperature regarding zirconia’s growth.


2011 ◽  
Vol 415-417 ◽  
pp. 585-589
Author(s):  
Dong Xin Wang ◽  
Xu Jin Bao ◽  
Jing Ming Zhong ◽  
Ben Shuang Sun

Using ammonia solution and tin chloride as the precursors: tin oxide nanoparticles with different particle sizes and morphologies were synthesised by varying the concentration, heating temperature and ripening time via hydrothermal method. The particles synthesised were characterised by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The TEM micrographs show that rod-like nanoparticles were synthesised when the SnCl4 solution concentration was less than 1.0 mol/L, which was changed to oval shape when the concentration increased above 2.0 mol/L. Polygonal shaped nanoparticles were observed at 220 °C for 48 hours. It was also found that changing temperature had little effect on the morphology but great influence on the size of the particles, which increased from 10 nm to 120 nm from 160 °C to 220 °C and 12 nm to 55 nm from 6 h to 48 h at 200 °C, respectively. XRD patterns indicated that all of nanoparticles synthesised were tin oxide.



2003 ◽  
Vol 107 (38) ◽  
pp. 10470-10475 ◽  
Author(s):  
Feng Huang ◽  
Hengzhong Zhang ◽  
Jillian F. Banfield


Author(s):  
Necip Güven ◽  
Rodney W. Pease

Morphological features of montmorillonite aggregates in a large number of samples suggest that they may be formed by a dendritic crystal growth mechanism (i.e., tree-like growth by branching of a growth front).



Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 649
Author(s):  
Marco Capolupo ◽  
Paola Valbonesi ◽  
Elena Fabbri

The ocean contamination caused by micro- and nano-sized plastics is a matter of increasing concern regarding their potential effects on marine organisms. This study compared the effects of a 21-day exposure to 1.5, 15, and 150 ng/L of polystyrene microplastics (PS-MP, 3-µm) and nanoplastics (PS-NP, 50-nm) on a suite of biomarkers measured in the Mediterranean mussel Mytilus galloprovincialis. Endpoints encompassed immunological/lysosomal responses, oxidative stress/detoxification parameters, and neurotoxicological markers. Compared to PS-MP, PS-NP induced higher effects on lysosomal parameters of general stress. Exposures to both particle sizes increased lipid peroxidation and catalase activity in gills; PS-NP elicited greater effects on the phase-II metabolism enzyme glutathione S-transferase and on lysozyme activity, while only PS-MP inhibited the hemocyte phagocytosis, suggesting a major role of PS particle size in modulating immunological/detoxification pathways. A decreased acetylcholinesterase activity was induced by PS-NP, indicating their potential to impair neurological functions in mussels. Biomarker data integration in the Mussel Expert System identified an overall greater health status alteration in mussels exposed to PS-NP compared to PS-MP. This study shows that increasing concentrations of nanoplastics may induce higher effects than microplastics on the mussel’s lysosomal, metabolic, and neurological functions, eventually resulting in a greater impact on their overall fitness.



2020 ◽  
Vol 981 ◽  
pp. 73-77
Author(s):  
Nurul Ainaa Najihah Busra ◽  
Ramli Arifin ◽  
Sib Krishna Ghoshal ◽  
Rodziah Nazlan

Enhancing the optical performance of rare earth doped binary inorganic glasses is an ever-demanding quest. Samarium (Sm3+) doped zinc tellurite glasses containing Manganese (Mn) nanoparticles (NPs) with composition (59-x)TeO2-20ZnCl2-10ZnO-10Li2O-1Sm2O3-(x)Mn3O4, where x = 0 to 0.06 mol% are prepared by melt quenching technique. The role played by Mn NPs in enhancing the optical behaviors are analyzed and discussed. The XRD patterns confirm the amorphous nature of the glass. The UV-Vis-NIR spectra reveal seven prominent absorption bands of Sm3+ ions. The photoluminescence spectra display four peaks corresponding to 4G5/2→6H5/2, 4G5/2 →6H7/2, 4G5/2→6H9/2 and 4G5/2 →6H11/2 transitions. An enhancement in the luminescence intensity is observed up to 0.05 mol% concentration of NPs and the intensity quenches beyond it. The enhancement is attributed to local electric field effect of NPs in the proximity of Sm3+ ion. Our results on improved optical response via precise control of NPs contents may be useful for the development of solid state lasers and amplifiers.



2020 ◽  
Vol 49 (6) ◽  
pp. 465-472
Author(s):  
S. Raj Sachin ◽  
T. Kandasamy Kannan ◽  
Rathanasamy Rajasekar

Purpose The purpose of this study is to carry out an investigation of the role of the wood particle size on the mechanical properties of poly lactic acid (PLA)-reinforced neem fiber biocomposite. Design/methodology/approach Composite test specimens were processed by reinforcing neem wood flour (NWF) in two different particle sizes, micro-sized NWF (MNWF) and nano-sized NWF (NNWF) separately into PLA. Composites were extruded at four different fiber loadings (10, 15, 20 and 25 Wt.%) into PLA matrix. The MNWF and NNWF had particle sizes varying from 5 to 15 µm and 10 to 15 nm, respectively. Findings Tensile strength, flexural strength and impact strength of PLA increased with fiber reinforcement for both the MNWF and NNWF cases. The NNWF-reinforced PLA composite at 20 Wt.% fiber loading proved to be the best composite that had outstanding mechanical properties in this research. Practical implications The developed composite can be used as a substitute for conventional plywood for furniture, building infrastructure and interior components for the automobile, aircraft and railway sectors. Originality/value A new biocomposite had been fabricated by using PLA and NWF and had been tested for its mechanical characteristics.





2015 ◽  
Vol 1112 ◽  
pp. 47-52 ◽  
Author(s):  
Frida Ulfah Ermawati ◽  
Suasmoro Suasmoro ◽  
Suminar Pratapa

A study of liquid mixing route to synthesize high purity Mg0.8Zn0.2TiO3 nanopowder, a candidate dielectric ceramics, has been successfully performed. Formation of the phases on the dried powder was studied using TG/DTA, XRD and FT-IR data. Rietveld analysis on the collected XRD patterns confirmed the formation of solid solution in the system. Such solid solution can be obtained from the powder calcined at 500 °C, but calcination at 550 °C gave rise to the most optimum molar purity up to 98.5% without intermediate phases. The role of Zn ions on the formation of solid solution was also discussed. Homogeneity of particle size distribution and nano-crystallinity of the system was verified from the particle size analyzer data, TEM image and the Rietveld analysis output.



2016 ◽  
Vol 30 (11) ◽  
pp. 9014-9021 ◽  
Author(s):  
Andrey S. Stoporev ◽  
Andrey Yu. Manakov ◽  
Lubov’ K. Altunina ◽  
Larisa A. Strelets


2015 ◽  
Vol 25 (29) ◽  
pp. 4700-4707 ◽  
Author(s):  
David C. Green ◽  
Rebecca Boston ◽  
Stefan Glatzel ◽  
Martin R. Lees ◽  
Stuart C. Wimbush ◽  
...  


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