Synthesis of TiO2 and F-Doping TiO2 Powders via "Reverse" Hydrolysis of Titanium Tetraisopropoxide

2015 ◽  
Vol 1085 ◽  
pp. 95-100 ◽  
Author(s):  
Elena Fakhrutdinova ◽  
Anastasiia V. Shabalina ◽  
Elena Sudareva
Keyword(s):  
Heat Treatment ◽  
Particle Size ◽  
Phase Transformation ◽  
Rutile Phase ◽  
Bet Surface Area ◽  
Titanium Tetraisopropoxide ◽  
Prolonged Heat ◽  
Hydrolysis Of ◽  
Prolonged Heat Treatment ◽  
Reverse Hydrolysis

TiO2 and F-TiO2 powders were prepared by hydrolysis of titanium tetraisopropoxide with reversed mixing of different hydrolytic reagents. The typeof the hydrolytic agentstronglyinfluences particle size, morphology and phase composition ofpowder.It was found, that the amount of injected water is significantly affects on BET surface area and particle size ofbare TiO2.The presence offluorinemakes the samplemore porous and preventsanatase to rutile phase transformation under prolonged heat treatment, also particle formed are bigger in comparison with un-doped TiO2.

Long-term stability of ICPCVD a-Si under prolonged heat treatment

2014 ◽  
Author(s):  
Kirsten L. Brookshire ◽  
Mariusz Martyniuk ◽  
K. K. M. B. Dilusha Silva ◽  
Yinong Liu ◽  
Lorenzo Faraone
Keyword(s):  
Heat Treatment ◽  
Term Stability ◽  
Long Term Stability ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

Prolonged heat treatment of Bi-Sr-Ca-Cu-O superconducting ceramics

1992 ◽  
Vol 131 (1) ◽  
pp. 369-370
Author(s):  
M. Kalnberga ◽  
I. Popova ◽  
A. Sternberg ◽  
A. Gajevskis
Keyword(s):  
Heat Treatment ◽  
Superconducting Ceramics ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

scholarly journals Cation Assisted Lattice Improvement of Highly Siliceous ZSM-5 upon Prolonged Heat Treatment

1986 ◽  
Vol 15 (9) ◽  
pp. 1523-1526 ◽  
Author(s):  
Bettina Kraushaar ◽  
Jan W. de Haan ◽  
Leo J. M. van de Ven ◽  
Jan H. C. van Hooff
Keyword(s):  
Heat Treatment ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

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.

scholarly journals Researches in the field of composite HCBS and of the refractory materials on their base in the Al2O3‒SiO2‒SiC system. Part 2

2018 ◽  
pp. 22-27 ◽  
Author(s):  
Yu. E. Pivinskii ◽  
P. V. Dyakin
Keyword(s):  
Heat Treatment ◽  
Refractory Materials ◽  
Bend Strength ◽  
Oxidation Degree ◽  
Dispersion Degree ◽  
System Part ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

The influence was investigated of the prolonged heat treatment on the samples properties prepared on base of the composite Al2O3‒SiO2‒SiC HCBS. The dispersion degree of the samples containing either 10 or 30 % of SiC varied within 3‒200 microns. The estimating method was proposed for the SiC oxidation degree in the composite. Depending on the samples composition the oxidation degree was within 50‒100 %. The ultimate bend strength and compressing strength SiC-containing samples attained the values of 80 and 390 MPa respectively. `````````````````````````````

A radioactive mineral from Mozambique related to davidite

1950 ◽  
Vol 29 (209) ◽  
pp. 101-112 ◽  
Author(s):  
F. A. Bannister ◽  
J. E. T. Horne
Keyword(s):  
Heat Treatment ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
British Museum ◽  
Crystalline Material ◽  
X Ray ◽  
Radioactive Mineral ◽  
Southern Rhodesia ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

Early in 1947 a black, opaque, radioactive mineral resembling samarskite in appearance was discovered at Mavnzi in the Tete distrier of Mozambique, Portuguese East Africa. Two small specimens, one a rough twinned crystal with trigonal symmetry (fig. 3), were sent by h. M. Macgregor; then Director of the Geological Survey of Southern Rhodesia, to the British Museum (Natural History) for investigation, and a chemical analysis by E. Golding (table I, no. 2) followed later in the same year. X-ray photographs of fragments and powder from both specimens were taken, but revealed on development no diffraction spots, lines, or haloes. Only after prolonged heat-treatment could powder lines characteristic of crystalline material be obtained. The metamict nature of the mineral before heat-treatment is not unexpected in view of its chemical composition, optical isotropy, and glassy fracture.

scholarly journals Sol-Gel Synthesis of TiO2 Nanocrystalline Particles with Enhanced Surface Area through the Reverse Micelle Approach

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Mohammad Hossein Nateq ◽  
Riccardo Ceccato
Keyword(s):  
Particle Size ◽  
Surface Area ◽  
Particle Density ◽  
Sol Gel ◽  
Bet Surface Area ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
Reflux Time ◽  
Nanocrystalline Particles ◽  
Time Extension

Titania nanocrystalline particles were synthesized by hydrolysis-condensation of titanium tetraisopropoxide in water-in-oil micellar solutions of water/cyclohexane/Triton X-100 system, and the effects of reflux time and water-to-surfactant molar ratio on the particle uniformity, crystallinity, and surface area were studied. Several characterization techniques including TEM and SEM, as well as X-ray diffraction and FT-IR spectroscopy, helium pycnometry, and nitrogen physisorption, were employed to evaluate the particle density and dimensions, crystallite size, surface area value, and the porosity features in the as-prepared condition and also after thermal treatment at 500°C. The results show that all treated samples are dense nanocrystalline anatase particles with BET surface area values over 100 m2·g−1 and primary particle size of 10–15 nm. However, for the as-prepared samples, as the reflux time increases, a better purification of particles from the synthesis environment is resulted, leading to denser and more crystalline powders with smaller particle size and higher BET surface area values culminating in 179 m2·g−1 for 24 hours of refluxing. Moreover, decreasing the water-to-surfactant molar ratio from 10 to 5 and 2 increases the particles surface area to 239 and 224 m2·g−1, respectively, at the expense of slight density and crystallinity degradation and considerable prolongation of surfactant removal step. Supportively, the comparison between photocatalytic activities of as-prepared samples also evidences the effectiveness of reflux time extension on improving the sample features and enhancing their functionality. This study can highlight how the earlier synthesis steps can influence the evolution of the structure of the final products.

Effect of prolonged heat treatment from 48°C to 63°C on toughness, cooking loss and color of pork

Meat Science ◽  
2011 ◽  
Vol 88 (2) ◽  
pp. 280-285 ◽  
Author(s):  
Line Christensen ◽  
Per Ertbjerg ◽  
Margit Dall Aaslyng ◽  
Mette Christensen
Keyword(s):  
Heat Treatment ◽  
Cooking Loss ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

scholarly journals PROLONGED HEAT TREATMENT FOR THE CONDUCTIVITY OF ALUMINUM-MAGNESIUM CERAMICS

2020 ◽  
pp. 21-23
Author(s):  
Андрух Сергій Леонідович ◽  
Галушка Сергій Анатолійович
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Oxide Ceramics ◽  
Conductive Materials ◽  
Additional Processing ◽  
Technical Properties ◽  
Prolonged Heat ◽  
Prolonged Heat Treatment

In their work they tried to reveal the use of oxide ceramics for high- temperature insulation and conductive materials. The effect of prolonged temperature on its electrical conductivity was studied. The table shows the physical and technical properties of ceramics after additional processing at a temperature of 1700°С.

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