Distribution of Additives in Single-Modified TiO2

2012 ◽  
Vol 1373 ◽  
Author(s):  
Marta A. Gleń ◽  
Barbara U. Grzmil
Keyword(s):  
Solid Solution ◽  
Phase Transformation ◽  
Phase Composition ◽  
Rutile Phase ◽  
Selective Leaching ◽  
Ft Ir ◽  
Selective Leaching Method ◽  
Zirconium Addition

ABSTRACTIn the present work the influence of different modifiers, calculated to B2O3, CeO2, Sb2O3, ZnO, and ZrO2, on their distribution in TiO2 is investigated. The phase composition and phase transformation of prepared rutile-TiO2 is determined by the selective leaching method, ICP-AES, XRD and FT-IR techniques. The addition of Sb2O3 to TiO2 has no influence on the anatase–rutile phase transformation, CeO2 and ZrO2 act as inhibitors of the TiO2 phase transformation and the addition of ZnO or B2O3 to TiO2 accelerates rutile formation. It is observed that boron is located in TiO2 in the form of soluble B2O3, zinc partly reacts with titanium forming co-phase TiZn2O4 and antimony addition to TiO2 presumably causing the formation of a co-phase of Sb with Ti. Cerium forms a separate phase, CeO2, and reacts partly with titanium, probably creating co-phase, CexTi(1-x)O2 (for example Ce0.8Ti0.2O2). Zirconium addition in TiO2 forms separate ZrO2 phase and solid solution of Zr with Ti.

Effect of CeO2 and Sb2O3 on the phase transformation and optical properties of photostable titanium dioxide

2011 ◽  
Vol 65 (2) ◽  
Author(s):  
Marta Gleń ◽  
Barbara Grzmil ◽  
Joanna Sreńscek-Nazzal ◽  
Bogumił Kic
Keyword(s):  
Phase Transformation ◽  
Titanium Dioxide ◽  
Optical Properties ◽  
Rutile Phase ◽  
Spectrophotometric Analysis ◽  
Grey Tone ◽  
Rutile Titanium Dioxide ◽  
Selective Leaching Method ◽  
Tio2 Phase ◽  
Xrd Method

AbstractIn the present work, the effect of individual additives calculated as molar fractions of Sb2O3 and CeO2 (x Sb 2O3 range: 0.03–0.08 %, x CeO 2 range: 0.05–0.14 %), on the phase composition, phase transformation, and optical properties of photostable rutile titanium dioxide was studied using selective leaching method, ICP-AES technique, XRD method, spectrophotometric analysis and S BET measurements. The starting material was hydrated titanium dioxide. It was observed that the addition of Sb2O3 to TiO2 did not influence the anatase-rutile phase transformation, but increasing the CeO2 addition caused a decrease in the rutilization degree. Thus, CeO2 acted as an inhibitor of the TiO2 phase transformation. Sb2O3 addition to TiO2 presumably caused the formation of a co-phase of Sb with Ti. Cerium formed a separate phase, CeO2, and reacted partly with titanium, probably creating co-phase, Ce0.8Ti0.2O2. Comparing the colour of modified rutile titanium dioxide according to the type of the additive introduced, it was found that TiO2 with CeO2 had higher brightness but lower white tone values when compared with TiO2 modified with Sb2O3. The relative lightening power and grey tone of the modified TiO2 were higher in TiO2 modified with Sb2O3. The values of the photocatalytic activity measured in all TiO2 samples modified either with Sb2O3 or CeO2 were very similar and varied around the value of 21.

Anatase-Type Ti1-2xNbxAlxO2 Solid Solution/Silica (SiO2) Composite Nanoparticles: Synthesis, Phase Stability, and Photocatalytic Performance

2010 ◽  
Vol 654-656 ◽  
pp. 2735-2738
Author(s):  
Masanori Hirano ◽  
Norio Kuno
Keyword(s):  
Solid Solution ◽  
Phase Transformation ◽  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Rutile Phase ◽  
Silica Content ◽  
Composite Nanoparticles ◽  
Hydrothermal Conditions ◽  
Nanoparticles Synthesis ◽  
Hydrolysis Of

Composite nanoparticles (anatase-type Ti1-2XNbXAlXO2 solid solution/SiO2) were directly synthesized from precursor solutions in the presence of urea under mild hydrothermal conditions at 180 °C for 5 h. The crystallite size of anatase was gradually decreased with increased silica content in the composite nanoparticles formed under weakly basic hydrothermal conditions via the hydrolysis of urea. The composite nanoparticles with composition Ti0.9Nb0.05Al0.05O2/SiO2 = 100/10 mol% showed good photocatalytic activity. The anatase-to-rutile phase transformation in the course of heating in air was retarded to maintain the anatase-type structure up to more than 1050 °C without a trace of rutile phase by the formation of composite nanoparticles (Ti0.90Nb0.05Al0.05O2/SiO2 = 100/20 mol%) with amorphous silica.

Pigmentary properties of rutile TiO2 modified with cerium, phosphorus, potassium, and aluminium

2013 ◽  
Vol 67 (11) ◽  
Author(s):  
Marta Gleń ◽  
Barbara Grzmil
Keyword(s):  
Titanium Dioxide ◽  
Optical Properties ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Xrd Analysis ◽  
Transformation Rate ◽  
Selective Leaching ◽  
P2o5 Content ◽  
Selective Leaching Method ◽  
Hydrated Titanium

AbstractThe influence of different modifiers, phosphorus, potassium, aluminium, and cerium on the pigmentary properties of TiO2 was studied. The phase composition and distribution of modifiers in prepared TiO2 products was investigated using XRD analysis, the selective leaching method, and ICP-AES technique. The optical properties, photoactivity, morphology, and surface area of modified TiO2 were determined by spectrophotometric, fluorescent, SEM, and BET measurements. The research was directed towards obtaining a pigmentary TiO2 with the highest possible photostability. It was found that the final calcination temperature, at which the anatase-rutile transformation rate was > 97 %, depended on the kind and amount of the modifiers introduced into hydrated titanium dioxide. In comparing the colour of TiO2 products modified with Ce, it was found that the addition of K to the TiO2 series caused an increase in all the optical properties examined. The presence of K and Al in TiO2 modified with Ce resulted in decreased photocatalytic activity. The photostability of TiO2 modified with Ce and K improved with an increase in P2O5 content. The highest photostability was measured for the TiO2-CePKAl series. It was concluded that the differences in both the optical properties and photoactivity of TiO2 depended on its phase composition and the distribution of modifiers in the products obtained.

Synthesis of Ti(C,N)/Al2O3 by Mechanically Induced Self-Propagating Reactive Synthesis

2011 ◽  
Vol 695 ◽  
pp. 437-440
Author(s):  
Jian Feng Zhu ◽  
Lan Ye ◽  
Hai Tong ◽  
Fen Wang
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Phase Transformation ◽  
Phase Composition ◽  
Flexural Strength ◽  
Good Combination ◽  
Powder Morphology ◽  
Reactive Synthesis ◽  
Morphology Characteristics

Ti(C,N)/Al2O3in situ solid solution composites have been synthesized by mechanically induced self-propagating reactive synthesis (MSR) from the mixture of Ti, Al, C and TiO2in nitrogen milling atmosphere. The phase transformation and powder morphology characteristics were studied by using XRD and SEM. Full dense and pure Ti(C,N)/Al2O3composites were fabricated at 1450 °C for 1 h under 10 MPa. The phase composition, microstructure and some mechanical properties of the composites were investigated. The results show that the synthesized Ti(C,N)/Al2O3composites posses a density of 4.66 g/cm3and a good combination of mechanical properties of hardness of 25.54 GPa and the flexural strength of 404 MPa. The reaction process mechanism was also discussed.

scholarly journals Unexpected Link between the Template Purification Solvent and the Structure of Titanium Dioxide Hollow Spheres

Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 112
Author(s):  
Tamás Gyulavári ◽  
Kata Kovács ◽  
Klára Magyari ◽  
Kornélia Baán ◽  
Anna Szabó ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Activity ◽  
Phase Composition ◽  
Anatase Phase ◽  
Hollow Spheres ◽  
Rutile Phase ◽  
Carbon Sphere ◽  
Carbon Spheres ◽  
Carbonate Species ◽  
Determining Factor

Carbon spheres were applied as templates to synthesize titanium dioxide hollow spheres. The templates were purified with either ethanol or acetone, and the effects of this treatment on the properties of the resulting titania were investigated. The photocatalytic activity of the catalysts was measured via the decomposition of phenol model pollutant under visible light irradiation. It was found that the solvent used for the purification of the carbon spheres had a surprisingly large impact on the crystal phase composition, morphology, and photocatalytic activity. Using ethanol resulted in a predominantly rutile phase titanium dioxide with regular morphology and higher photocatalytic activity (r0,phenol = 3.9 × 10−9 M∙s−1) than that containing mainly anatase phase prepared using acetone (r0,phenol = 1.2 × 10−9 M∙s−1), surpassing the photocatalytic activity of all investigated references. Based on infrared spectroscopy measurements, it was found that the carbon sphere templates had different surface properties that could result in the appearance of carbonate species in the titania lattice. The presence or absence of these species was found to be the determining factor in the development of the titania’s properties.

A Simple Dissolved Metals Mixing Route to Prepare Nanostructured Mg0.8Zn0.2TiO3 Solid Solution

2015 ◽  
Vol 1112 ◽  
pp. 47-52 ◽  
Author(s):  
Frida Ulfah Ermawati ◽  
Suasmoro Suasmoro ◽  
Suminar Pratapa
Keyword(s):  
Solid Solution ◽  
Particle Size ◽  
Rietveld Analysis ◽  
Dissolved Metals ◽  
Intermediate Phases ◽  
Particle Size Analyzer ◽  
Ft Ir ◽  
Xrd Patterns ◽  
Zn Ions

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.

Changes in the structure of a thermal protective aluminum-nickel coating under the influence of a single thermal laser pulse

2021 ◽  
Vol 4 ◽  
pp. 25-30
Author(s):  
O. B. Berdnik ◽  
◽  
P. Yu. Kikin ◽  
V. N. Perevezentsev ◽  
E.N. Razov ◽  
...  
Keyword(s):  
Solid Solution ◽  
Heat Flux ◽  
Phase Composition ◽  
Nickel Coating ◽  
Microstructural Analysis ◽  
Radiation Energy ◽  
Heat Fluxes ◽  
Initial State ◽  
Nial Phase ◽  
Ni3al Phase

The regularities of changes in the structure and phase composition of the thermal protective aluminide-nickel coating (Ni — 45 %; Al — 14 %; Co — 22 %; Cr — 18.9 %; Fe — 0.15 %; Nb — 0.14 %; Y — 0.09 %; Ca — 0.06 %; Mn — 0.01 %; C — 0.15 %; Si — 0.15 %; S — 0.006 %) after exposure to short-term pulsed heat fluxes of various power, created by the radiation of a pulse-periodic laser LRS-150A with a radiation wavelength λ = 1.06 µm and a pulse duration τ = 12·10–3 s. The radiation energy was E = 5, 10, and 15 J. Microstructural analysis and the elemental composition of the resulting coating were carried out as well as analysis of the phase composition. X-ray microanalysis of the coating was also carried out. In the initial state and after irradiation of the coating with a heat flux of power P = 7·103 W/cm2, light microregions are observed in the micrographs of the surface. These regions do not have clearly defined external boundaries and consist of the NiAl phase and a small amount of the Ni3Al phase with the presence of inclusions of particles containing a solid solution of Ni – Co – Cr. After irradiation of the coating with heat fluxes of higher power (P = 1.7·104 W/cm2 and P = 2.2·104 W/cm2), large convex formations appeared on its surface, consisting mainly of Ni3Al and NiAl phases. On micrographs of the surface, they appear as white areas with well-defined outer boundaries. The content of the Ni3Al phase in them in comparison with the initial state increased, and the content of the NiAl phase decreased, while the particles of inclusions of Ni, Co, and Cr disappeared. It can be assumed that an increase in the Ni3Al content is associated with the dissolution of particles of a solid solution of Ni – Co and Cr in the melt and the subsequent diffusion of nickel into the NiAl phase. When exposed to a heat flux of power P = 2.2·104 W/cm2, microcracks appear on the areas of the coating surface covered with aluminum oxide.

Performance Studies on In Situ Spinel Solid Solution Bonded Periclase Refractories

2014 ◽  
Vol 633 ◽  
pp. 245-248
Author(s):  
Xin Lin ◽  
Yong Li ◽  
Yan Jing Li ◽  
Jun Jie Zhang ◽  
Chang He Gao ◽  
...  
Keyword(s):  
Solid Solution ◽  
Phase Composition ◽  
Performance Studies ◽  
Magnesium Aluminate ◽  
Spinel Solid Solution ◽  
Magnesium Aluminate Spinel ◽  
Crushing Strength ◽  
Cold Crushing Strength ◽  
Shock Resistance

Specimens were prepared using iron-rich magnesia (3~1 mm、≤1 mm) and high purity magnesia (≤0.088 mm) as the main starting materials, adding tabular alumina at different size (3~2、2~1、≤1 mm) and content:3%、6%、9%、12%、15% to discover the influence of tabular alumina on sample performance. Phase composition and microstructure were also analyzed. The results show that specimen with content of 6% of corundum possessed the best comprehensive performance:apparent porosity 17%, bulk density 2.95 g·cm-3, cold crushing strength 74 MPa, refractoriness under load 1700 °C, heat shock resistance of up to 18 times. The formations of magnesium aluminate spinel and hercynite solid solution were enhanced by Fe ion at high temperatures in the iron-rich magnesia-corundum system at the presence of iron oxides, which are able to largely dissolved in periclase.

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