ZnO Zincite Research Articles

Material composition and microstructure of ceramic glass й hearth of blast furnace No. 6 of JSC EVRAZ NTMK after service. Refractory microstructure after service

The results of a comprehensive study of the material microstructure of refractory samples after service in the furnace of a blast furnace with a useful volume of 2200 m3 for 14 years are presented. Structural and genetic analysis established a characteristic sequence of processes of degeneration and wear of the ceramic furnace stack, including 6 stages: the formation of micro-and macro-cracks; condensation of vaporous zinc; zinc oxidation with the formation of fire-resistant ZnO zincite and the deposition of carbon black by the; chemical interaction of zinkite with mullite and corundum to form ZnAl2O4 ganite and 2ZnO·SiO2 willemite; partial oxidation of silicon carbide with the release of silica glass SiO2, eutectic melt of complex composition, and wellimite. Due to intensive accumulation of capillary pores, infiltration of the slag melt in the volume of refractories does not occur. Wear of refractories in the furnace has a complex, mainly thermochemical mechanism and a low speed due to the formation of a garnish containing refractory compounds. Ill. 5. Ref. 14.

Crystalline Structure and Thermal Stability of an Unknown ZIF-L300 Phase.

In recent years, the synthesis, crystalline structure, and applications of zeolite imidazole frameworks (ZIFs) have attracted extensive attention. Since the ZIF-L phase was synthesized, a new phase was observed during the heating process, but its crystal structure is unknown. The unknown new phase, which was named ZIF-L300 in this study, was confirmed again. In this study, the X-ray powder diffraction technique and Rietveld refinement were used to solve the crystalline structure of the unknown ZIF-L300 phase. The results demonstrate that ZIF-L300 has the same chemical formula (ZnC8N4H10) as in ZIF-8 and belongs to a hexagonal structure with a space group of P61. The lattice parameters have been determined as follows: a = b = 8.708(7) Å, c = 24.195(19) Å, α = β = 90°, and γ = 120°. The X-ray absorption fine structure (XAFS) technique was also used to extract the local atomic structures. The in situ X-ray diffraction (XRD) technique was used to monitor the structural evolution of the as-prepared ZIF-L in a temperature range from room temperature to 600 °C. The results show that the sample experiences a change process from the initial ZIF-L orthorhombic phase (<210 °C), to the ZIF-L300 hexagonal phase (∼300 °C), then to an amorphous phase (∼390 °C), and finally to a zincite ZnO phase (>420 °C). These sorts of structural information are helpful to the application of ZIF materials and enrich the knowledge of the thermal stability of ZIF materials.

Experimental Liquidus Studies of the ZnO-“CuO0.5” and ZnO-“CuO0.5”-SiO2 Liquidus in Equilibrium with Cu-Zn Metal

Phase equilibria in the ZnO-“CuO0.5”-SiO2 system have been investigated at 1403-1948 K (1130-1675 °C) for oxide liquid in equilibrium with Cu-Zn metal (> 99% Cu) and solid oxide phases: (a) tridymite or cristobalite SiO2; (b) willemite Zn2SiO4; (c) zincite ZnO; and (d) cuprite Cu2O. Two-liquid immiscibility range in the high-SiO2 slags has also been studied. High-temperature equilibration on primary phase (SiO2, Cu2O), inert metal (platinum-iridium wire), or ceramic (Al2O3 for high-Cu2O slags) substrates, followed by quenching and direct measurement of Zn, Cu, Si and possible impurities (Al, Pt, Ir) concentrations in the phases with the electron probe x-ray microanalysis (EPMA) has been used to accurately characterize the system in equilibrium with metal. All results are projected onto the ZnO-“CuO0.5”-SiO2 plane for presentation purposes.

CONSERVATION OF THE FLOWERS CANVAS PAINTING (1) AT THE EGYPTIAN AGRICULTURAL MUSEUM

The present study aims to examine and treat the flowers canvas painting at the Egyptian Agric-ultural Museum. It is divided into three parts: a) USBDM, SEM-EDX, XRD, GC and FTIR studies, which revealed that the object is suffering from deterioration forms, e.g. ruptures, dust, cracks, missing parts, brittleness, fragility, acidified canvas, and incompatible treatments. The coloring materials are: The green is celadonite (K(Ca, Mg, Fe2) (Fe3Al) [Si4O10](OH)2), the red is hematite (Fe2O3), the blue is lazurite (Na,Ca)8(AlSiO4)6(SO4,S,Cl)2), the beige is hematite (Fe2O3) mixed with barite (BaSO4) and zincite (ZnO), and the gray is carbon black (C). Additionally the ground layer consists of hydrocerussite PbCO3.(OH)2, cerussite Pb3CO3 and zincite ZnO binded with animal glue. The oil media is the poppy seed oil. b) The experimental part showed that 7% Beva371 in toluene is more suitable than the fish glue for object consolidation. c) The applied part covered cleaning, consolidation, patching, lining, completing the missing parts in the painting and ground layers and varnishing.

Study of the inhibition ability of benzotriazole on the Zn-Mg coated steel corrosion in chloride electrolyte

The corrosion inhibition of Zn-Mg coated steel by benzotriazole was investigated in sodium chloride solution. Electrochemical and analytical measurements combined with surface analyses indicate that benzotriazole inhibits the corrosion reactions by forming a complex between Zn2+ and the anionic form of benzotriazole BTA− present near the surface where pH increases due to Mg dissolution. The complex reinforces the corrosion product layer composed of zincite ZnO which precipitates on the surface. If a benzotriazole/chloride ions ratio of 1/100 is respected and if the presence of the inhibitor is always maintained in the chloride medium, a sustainable barrier layer is assured.

Morphology-controllable growth of vertical ZnO nanorod arrays by a polymer soft template method: Growth mechanism and optical properties

Vertically well-aligned ZnO nanorod arrays were synthesized on silicon substrate by a novel polymer soft template method. The ZnO nanorod arrays have been deposited by immersing a silicon substrate into an aqueous solution containing Zn(CH3COO)2·2H2O, Polyvinylpyrrolidone (PVP) and NH3·H2O at 99 °C and then being annealed in oxygen atmosphere. The effects of reaction conditions on the morphology, structure and optical properties of ZnO nanostructures were investigated. The morphology of ZnO nanostructures was demonstrated to be controllable by adjusting the pH values of PVP-Zn2+ complex solution, zinc acetate concentration and growth time, respectively. The nanorod arrays were hexagonal zincite ZnO and the c-axis orientation growth trend of ZnO became more and more obvious with increasing the pH values of PVP-Zn2+ complex solution from 7.5 to 10.5, the zinc acetate concentration from 5 mM to 200 mM, and the growth time from 1 h to 3 h, respectively. The concentration of deep level defects in ZnO was reducing with increasing the pH values of PVP-Zn2+ complex solution, zinc acetate concentration and growth time, respectively. A growth mechanism of vertical ZnO nanorod arrays based on PVP soft template is proposed.

Structural and Optical Characterization of TiO&lt;sub&gt;2&lt;/sub&gt;/ZnO Thin Films Prepared by Sol-Gel Method

Thin film has been extensively study due to better structural, surface morphology, and optical properties. The combination of two materials will enhance the properties of thin film. In this study, TiO2/ZnO thin films were deposited on glass substrates via sol-gel method. TiO2 acts as pre-deposited thin film with calcination temperatures at 400 °C, 500 °C, and 600 °C. The post-deposition of TiO2/ZnO thin films were calcined at 500 °C and 600 °C. TiO2 sol-gel was synthesis from titanium (IV) butoxide and butanol as the precursor, while ZnO sol-gel was synthesis from zinc acetate dehydrate and isopropanol as the precursor. The TiO2/ZnO thin films were characterized by X-ray diffraction (XRD), atomic force microscope (AFM), and ultraviolet visible spectroscopy (UV-Vis). The effect of calcination temperature and pre-deposited TiO2 thin films show difference results of bilayer thin films. The XRD analysis shows all TiO2/ZnO thin films growth with TiO2 anatase crystalline phase at orientation (1 0 1) and ZnO zincite phase at orientation (1 0 1). The structural properties of TiO2/ZnO thin films were improved by controlling the calcination temperature. Based on AFM analysis, the RMS value for TiO2/ZnO decreases as the calcination temperature increased. The compacted and dense surface roughness were controlled by the temperature. Meanwhile, the percentage of thin film ultraviolet transmittance can be enhanced with combination of two materials, TiO2 and ZnO. Therefore, the pre-deposited layer of thin film with influenced by calcination temperature will improve the crystallinity, surface morphology, and optical properties of TiO2/ZnO thin films.

Preparation and antibacterial properties of titanium-doped ZnO from different zinc salts

To research the relationship of micro-structures and antibacterial properties of the titanium-doped ZnO powders and probe their antibacterial mechanism, titanium-doped ZnO powders with different shapes and sizes were prepared from different zinc salts by alcohothermal method. The ZnO powders were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED), and the antibacterial activities of titanium-doped ZnO powders on Escherichia coli and Staphylococcus aureus were evaluated. Furthermore, the tested strains were characterized by SEM, and the electrical conductance variation trend of the bacterial suspension was characterized. The results indicate that the morphologies of the powders are different due to preparation from different zinc salts. The XRD results manifest that the samples synthesized from zinc acetate, zinc nitrate, and zinc chloride are zincite ZnO, and the sample synthesized from zinc sulfate is the mixture of ZnO, ZnTiO3, and ZnSO4 · 3Zn (OH)2 crystal. UV-vis spectra show that the absorption edges of the titanium-doped ZnO powders are red shifted to more than 400 nm which are prepared from zinc acetate, zinc nitrate, and zinc chloride. The antibacterial activity of titanium-doped ZnO powders synthesized from zinc chloride is optimal, and its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) are lower than 0.25 g L−1. Likewise, when the bacteria are treated by ZnO powders synthesized from zinc chloride, the bacterial cells are damaged most seriously, and the electrical conductance increment of bacterial suspension is slightly high. It can be inferred that the antibacterial properties of the titanium-doped ZnO powders are relevant to the microstructure, particle size, and the crystal. The powders can damage the cell walls; thus, the electrolyte is leaked from cells.

THERMAL TREATMENT OF STAINLESS STEEL DUSTS FOR LEACHING

Many pyrometallurgical, hydrometallurgical and combined processes have been developed to allow better utilization of steelmaking dusts. The dusts contain metals and compounds that can harm the processes and one of these elements is zinc that is present in the flue dusts as zincite ZnO and franklinite ZnFe2O4. The effect of alkaline roasting on the dissolution of stainless steel flue dusts in acid and alkaline leaching was studied. The extraction of zinc from EAF dust was not significantly improved in alkaline leach (40 – 50 %) but there was indication of better extraction in acid leach (over 90 %). No improvement in extraction from AOD dust was seen either in alkaline (max. 58 %) or acid leach (max. 72 %). The acid leach of synthetic ferrite resulted in less than 32 % Zn recovery, and this must be studied further to find out the effect of franklinite in the dusts.

Microstructural characterization of chemical bath deposited and sputtered Zn(O,S) buffer layers

The present work aims at investigating the microstructure of Zn(O,S) buffer layers relative to their deposition route, namely either chemical bath deposition (CBD) or RF co-sputtering process (PVD) under pure Ar. The core of the study consists of cross-sectional transmission electron microscopy (TEM) characterization of the differently grown Zn(O,S) thin films on co-evaporated Cu(In,Ga)Se2 (CIGSe) absorbers. It shows that the morphology of Zn(O,S) layer deposited on CIGSe using CBD process is made of a thin layer of well oriented ZnS sphalerite-(111) and/or ZnS wurtzite-(0002) planes parallel to CIGSe chalcopyrite-(112) planes at the interface with CIGSe followed by misoriented nanometer-sized ZnS crystallites in an amorphous phase. As far as (PVD)Zn(O,S) is concerned, the TEM analyses reveal two different microstructures depending on the S-content in the films: for [S]/([O]+[S])=0.6, the buffer layer is made of ZnO zincite and ZnS wurtzite crystallites grown nearly coherently to each other, with (0002) planes nearly parallel with CIGSe-(112) planes, while for [S]/([O]+[S])=0.3, it is made of ZnO zincite type crystals with O atoms substituted by S atoms, with (0002) planes perfectly aligned with CIGSe-(112) planes. Such microstructural differences can explain why photovoltaic performances are dependent on the Zn(O,S) buffer layer deposition route.

Large scale synthesis of ZnO nanoparticles via homogeneous precipitation

In order to synthesize ZnO nanoparticles economically, industrial-grade zinc sulfate and urea were utilized to synthesize ZnO precursors in a stirred-tank reactor or a Teflon-lined autoclave at 100–180 °C under complete sealing condition. The ZnO precursors were calcined at 450 °C for 3 h to synthesize ZnO nanoparticles. The composition of the precursors and the formation mechanism of ZnO were studied by thermogravimetric analysis and Fourier transform infrared spectroscopy. The results of X-ray diffraction, transmission electron microscopy and scanning electron microscopy of the ZnO powders demonstrate that high-purity zincite ZnO nanoparticles are synthesized. Orthogonal experiments were performed to find out the optimal conditions for the maximum yield and the minimum size. The effect of temperature on the size of ZnO nanoparticles was investigated. The results show that a higher temperature is propitious to obtain smaller nanoparticles.

Investigation of phase transformations and photocatalytic properties of sol–gel prepared nanostructured ZnO/TiO 2 composites

A number of ZnO/TiO 2 nanocomposites were synthesized by a sol–gel method. The X-ray diffraction results indicated that the as-synthesized powder has anatase TiO 2, zincite ZnO, and two different Zn(OH) 2 phases. Heat treatment at 220 °C transforms all of Zn(OH) 2 phases into ZnO. Increasing calcinations temperature up to 680 °C produced Zn 2TiO 4 and ZnTiO 3 solid solutions in ZnO/TiO 2 system. With an increase in temperature, the amount of ZnTiO 3 phase decreased in a way that it totally disappeared at 900 °C and transformed into Zn 2TiO 4. Photocatalytic properties of the synthesized ZnO/TiO 2 nanocomposites and commercial ZnO photocatalyst were compared for the degradation of congo red azo dye. Among the various catalysts, the composite calcined at 420 °C showed the highest efficiency towards the removal of congo red.

Optical properties of zinc peroxide and zinc oxide multilayer nanohybrid films

Zinc peroxide and zinc oxide nanoparticles were prepared and self-assembled hybrid nanolayers were built up using layer-by-layer (LbL) technique on the surface of glass substrate using the layer silicate hectorite and an anionic polyelectrolyte, sodium polystyrene sulfonate (PSS). Light absorption, interference and morphological properties of the hybrid films were studied to determine their thickness and refractive index. The influence of layer silicates and polymers on the self-organizing properties of ZnO 2 and ZnO nanoparticles was examined. X-ray diffraction revealed that ZnO 2 powders decomposed to ZnO (zincite phase) at relatively low temperatures (less than 200 °C). The optical thickness of the films ranged from 190 to 750 nm and increased linearly with the number of layers. Band gap energies of the ZnO 2/hectorite films were independent from the layer thickness and were larger than that of pure ZnO 2 nanodispersion. Decomposition of ZnO 2 to ZnO and O 2 at 400 °C resulted in the decrease of the band gap energy from 3.75 to 3.3 eV. Concomitantly, the refractive index increased in correlation with the formation of the zincite ZnO phase. In contrast, the band gap energies of the ZnO 2/PSS hybrid films decreased with the thickness of the nanohybrid layers. We ascribe this phenomenon to the steric stabilization of primary ZnO 2 particles present in the confined space between adjacent layers of hectorite sheets.

Sintering behavior and electromagnetic properties of Fe-deficient NiZn ferrites

Sintering behavior and electromagnetic properties of Ni 0.5Zn 0.5Fe 2− x O 4−3/2 x ferrite ( x = 0, 0.4, 0.8) by the sol–gel method are investigated. Fe deficiency in the composition enhances sintering and retards grain growth. The near fully dense Fe-deficient samples could be obtained at a sintering temperature as low as 1120 °C and the highest relative density appears in the x = 0.8 sample sintered at 1150 °C. Second phase zincite ZnO resulting from Fe deficiency plays an important role in spinel NiZn ferrites by acting as a grain growth inhibitor and the grain growth of NiZn ferrite is effectively suppressed. When the sintering temperature is above 1200 °C, extensive grain growth occurs due to the probability of serious volatilization of zinc at high temperatures. The ratio of Ni to Zn of NiZn ferrites increases with increasing Fe deficiency due to the separation of zinc from spinel lattice, which results in the decrease in initial permeability and the increase in Curie temperature and resonant frequency.

Pulsed Laser Deposition and Fabrication of CoO/ZnO and CoO/TiO&lt;sub&gt;2&lt;/sub&gt; Nano-Hybrid Thin Film

Nano-hybrid CoO/ZnO and CoO/TiO2 thin films are interesting magnetic semiconductors, which may be the potential candidates in spintronic devices. We report a study of the morphology and properties of highly crystalline and textured CoO/ZnO and CoO/TiO2 nanohybrid thin films grown on Al2O3 (006) substrates by pulse laser deposition (PLD). The structural and magnetic properties of the deposited films were analyzed by AFM, SEM, XRD and AGM. Highly crystalline CoO/ZnO and CoO/TiO2 films were formed on single crystal Al2O3 substrates at 1x10-4 Torr oxygen partial pressure. It has been found that with a fine tune of the deposition conditions and heat treatment, the films can have highly crystalline ZnO zincite hexagonal and TiO2 rutile structure. The XRD rocking curves showed that the thin films grown are highly textured with FWHM of 0.251o for ZnO zincite and 0.065o for TiO2 rutile respectively. Both zincite and rutile exhibited properties of ferromagnetics above room temperature. The AGM results show that the saturation magnetization (Ms) is strongly dependent on substrate temperature.

High-pressure X-ray investigation of zincite ZnO single crystals using diamond anvils with an improved shape

A high-pressure cell for single-crystal investigations requires large opening angles. If it does not contain any beryllium but only two diamonds mounted on steel backing plates, normally only lower pressures can be attained without risk of disruption of the diamond anvils [Ahsbahs (2004).Z. Kristallogr.219, 305–308]. In order to enable pressures up to at least 10 GPa, specially shaped anvils were designed. In a first study with such anvils, the high-pressure behaviour of zincite ZnO was investigated up to the transition pressure of about 9.5 GPa. A slight decrease of the axial ratioc/awith increasing pressure was observed. The fit of the Birch–Murnaghan equation of state gave a bulk modulusK= 146.5 (8) GPa with a fixed pressure derivativeK′ = 4. During the phase transformation, the single crystals were destroyed. The pronounced preferred orientation of the obtained material, however, enabled the determination of the orientation relations between the low-pressure wurtzite-type and the high-pressure NaCl-type phase. The orientation relations are similar to those in CdS and CdSe.

A General Nonaqueous Route to Binary Metal Oxide Nanocrystals Involving a C−C Bond Cleavage

A widely applicable solvothermal route to nanocrystalline iron, indium, gallium, and zinc oxide based on the reaction between the corresponding metal acetylacetonate as metal oxide precursor and benzylamine as solvent and reactant is presented. Detailed XRD, TEM, and Raman studies prove that, with the exception of the iron oxide system, where a mixture of the two phases magnetite and maghemite is formed, only phase pure materials are obtained, gamma-Ga(2)O(3), zincite ZnO, and cubic In(2)O(3). The particle sizes lie in the range of 15-20 nm for the iron, 10-15 nm for the indium, 2.5-3.5 nm for gallium, and around 20 nm for zinc oxide. GC-MS analysis of the final reaction solution after removal of the nanoparticles showed that the composition is rather complex consisting of more than eight different organic compounds. Based on the fact that N-isopropylidenebenzylamine, 4-benzylamino-3-penten-2-one, and N-benzylacetamide were the main species found, we propose a detailed formation mechanism encompassing solvolysis of the acetylacetonate ligand, involving C-C bond cleavage, as well as ketimine and aldol-like condensation steps.

Three-Dimensional Array of Highly Oriented Crystalline ZnO Microtubes

The ability to generate homogeneous particulate thin films of highly oriented and highly porous microparticles of a post transition metal oxide onto polycrystalline and single-crystalline substrates, at low cost, by a template-free, aqueous low-temperature coating process is demonstrated by the fabrication of a large three-dimensional array of perpendicularly oriented hexagonal microtubes of crystalline zincite ZnO from an aqueous solution of zinc nitrate and methenamine.

Preparation, structure and thermal properties of a zinc copper maleate precursor Cu0.06Zn0.94C4O4H2 ·2H2O

J. Černák, J. Chomič, C. Kappenstein and F. Robert, J. Chem. Soc., Dalton Trans., 1997, 2981 DOI: 10.1039/A607839G

Spherical Particles of Pure and Manganese Doped Zinc Oxide and Zinc Hydroxicarbonate

AbstractPure and manganese doped zinc hydroxicarbonate are precursors for materials based on zinc oxide with electrical and luminescent properties. This paper reports on investigation of the effect of chloride and sulfate anions in the morphology of pure and doped precursors obtained by aging diluted zinc salt solutions in presence of urea, and their thermally decomposed products Characterization was carried out by XRI), IR and SEM techniques. Hydrozincite Zn5(OH)6(CO3)2 and zincite ZnO with spherical shaped particles of 5–10 ptm were obtained independent of anion used Moreover, in a chloride medium the spheres are organized in an arrangement of acicularly crystallized units as spherulitic aggregates, and in sulfate medium porous spherical particles were observed In addition, there is a good topotaxic relationship between the precursor and oxide