Preparation and Properties of Srn+1TinO3n+1 Ruddlesden-Popper Homologous Series by Metal-Citric Acid Complex Decomposition Method

2007 ◽  
Vol 1044 ◽  
Author(s):  
Keishi Nishio ◽  
Kazuhiko Fukuda ◽  
Tomohiro Imai ◽  
Hirohumi Takenouchi ◽  
Hideo Mae ◽  
...  
Keyword(s):  
Citric Acid ◽  
Homologous Series ◽  
Single Phase ◽  
Raw Materials ◽  
Chelating Agent ◽  
Uniaxial Pressure ◽  
Acid Complex ◽  
Starting Solution ◽  
Wide Range ◽  
High Dielectric

AbstractWe investigated the Srn+1TinO3n+1 Ruddlesden-Popper homologous series. This material exhibits a wide range of electric behaviors, from a high-dielectric-constant tunable-paraelectric in its undoped form to a metallic superconductor when it is doped with a variety of elements.The Srn+1TinO3n+1 and the yttrium-doped Srn+1TinO3n+1 Ruddlesden-Popper homologous series were prepared through the thermal decomposition of a metal citric acid complex. The starting solution consisted of the raw materials strontium acetate and titanium alkoxide. Citric acid was used as the chelating agent, and ethanol and distilled water were mixed and used as a solvent. Single phase Sr2TiO4 and Sr3Ti2O7 were produced without creation of SrCO3 by heat-treatment at 1073 and 1473 K, respectively, for three hours. We were unable to produce single phase Sr4Ti3O10. The samples consisted of Sr4Ti3O10 and SrTiO3 phases. Scanning electron microscopy showed that the grain shape of the Sr2TiO4 was plate-like, while those of the Sr3Ti2O7 and Sr4Ti3O10 were not and the grains had large numbers of pores. High-density Sr2-xYxTiO4 (x= 0 to 0.06) ceramic samples were produced under hot-press conditions (1823 K for one hour at a uniaxial pressure of 31.2 MPa). Although the undoped samples were insulators, the yttrium-doped samples showed high electrical conductivity (i.e. that of Sr1.98Y0.02TiO4 was ρ= 8.5×10−5 Ωcm). The Seebeck coefficient of Sr1.98Y0.02TiO4 was –160.7 μV/K, and the thermal conductivity was 3.38 W/mK.

Preparation of Delafossite CuYO2 by Metal-citric Acid Complex Decomposition Method

2009 ◽  
Vol 1166 ◽  
Author(s):  
Keishi Nishio ◽  
Tomomi Okada ◽  
Naoto Kikuchi ◽  
Satoshi Mikusu ◽  
Tsutomu Iida ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Citric Acid ◽  
Single Phase ◽  
Raw Materials ◽  
Chelating Agent ◽  
Amorphous Powder ◽  
Heat Treating ◽  
Acid Complex ◽  
Synthesis Conditions ◽  
Starting Solution

AbstractDelafossite CuYO2 and Ca doped CuYO2 were prepared by thermal decomposition of a metal-citric acid complex. The starting solution consisted of Cu acetate, Y acetate and Ca acetate as the raw materials. Citric acid was used as the chelating agent, and acetic acid and distilled water were mixed as a solvent. The starting solutions were heated at 723 K for 5 h after drying at 353 K. The obtained powders were amorphous and single phase of orthorhombic Cu2Y2O5 was obtained by heat-treated the amorphous powder at a temperature range between 1073 and 1373 K for 3 h in air. Furthermore, Heat-treating the obtained orthorhombic Cu2Y2O5 at above 1373 K in air caused it to decompose into Y2O3, CuO and Cu2O. On the other hand, the sample powder prepared from a starting solution without citric acid, i.e., single phase of orthorhombic Cu2Y2O5 could not be obtained under the same synthesis conditions as that for a solution with citric acid. We were able to obtain delafossite CuYO2 and Ca doped CuYO2 from orthorhombic Cu2Y2O5 under a low O2 pressure atmosphere at above 1223 K. The obtained delafossite CuYO2 composed hexagonal and rhombohedral phases. The color of the CuYO2 powder was light brown and that of Ca-doped CuYO2 was light green. Diffraction peaks in the XRD pattern were slightly shifted by doping Ca for CuYO2, and these peaks shifted toward to a high diffraction angle with an increasing amount of doped Ca. From these results, we concluded that Ca doped delafossite CuYO2 could be obtained by thermal decomposition of a metal-citric acid complex.

Preparation of LiFePO4 as a Cathode Material for Lithium Ion Batteries by a Citric Acid Complex Method

2006 ◽  
Vol 320 ◽  
pp. 259-262
Author(s):  
Masashi Higuchi ◽  
Kaori Uchida ◽  
Keiichi Katayama ◽  
Yasuo Azuma
Keyword(s):  
Particle Size ◽  
Citric Acid ◽  
Solid State ◽  
Single Phase ◽  
Lithium Ion ◽  
Solid State Reaction Method ◽  
Complex Method ◽  
Conventional Solid State Reaction ◽  
Acid Complex ◽  
Reaction Method

LiFePO4 powders were prepared by a citric acid complex method. The effects of source composition and firing conditions on the formation of LiFePO4 were investigated. Single phase and well-crystallized LiFePO4 powders were obtained at 500°C for 5h. The particle size of the obtained powder is smaller than that of powder prepared by the conventional solid-state reaction method.

scholarly journals Preparation of Single-phase High Entropy Carbides by a Modified Citric Acid Complexing Method

2021 ◽  
Author(s):  
Hu-Lin Liu ◽  
Feng-Zhen DANG ◽  
De-Wei NI ◽  
Chang-Qing LIU ◽  
Yun-Long XUE ◽  
...  
Keyword(s):  
Citric Acid ◽  
Single Phase ◽  
Raw Materials ◽  
Low Cost ◽  
Transition Metal Carbide ◽  
Synthesis Process ◽  
Step Process ◽  
High Entropy ◽  
One Step ◽  
Sluggish Diffusion

Abstract We developed a new method to synthesize single-phase transition metal carbide powders by combining citric acid complexing method and ball-milling dispersion. High-entropy carbides (Zr0.25Ti0.25Ta0.25Nb0.25)C (4TmC), (Zr0.2Ti0.2Ta0.2Nb0.2Hf0.2)C (5TmC-H) and (Zr0.2Ti0.2Ta0.2Nb0.2Mo0.2)C (5TmC-M) were successfully fabricated by this method using low-cost raw materials. The element and phase composition and microstructures of the obtained carbide powders were investigated. The relationships of synthesis process and temperature with chemical composition were also discussed. (Zr0.25Ti0.25Ta0.25Nb0.25)C can be obtained by a one-step process at 1550 °C, while (Zr0.2Ti0.2Ta0.2Nb0.2Hf0.2)C and (Zr0.2Ti0.2Ta0.2Nb0.2Mo0.2)C are fabricated by a two-step process of carbothermal reduction followed by solid solution at the temperatures not lower than 1850 °C and 1650 °C. The higher synthesis temperatures of the five-component carbides are attributed to the obvious sluggish diffusion effect induced by the larger lattice distortions. The particle sizes of (Zr0.25Ti0.25Ta0.25Nb0.25)C, (Zr0.2Ti0.2Ta0.2Nb0.2Hf0.2)C and (Zr0.2Ti0.2Ta0.2Nb0.2Mo0.2)C powders are 118.2±26.1 nm (at 1550 °C), 284.8±73.7 nm (at 1850 °C) and 65.5±13.9 nm (at 1750 °C), respectively.

Develop Single-Phase High Dielectric Constant SiO2-Based Composite Gate Dielectric

2010 ◽  
Vol 434-435 ◽  
pp. 259-262
Author(s):  
Chao Chin Chan ◽  
Yin Fang Wei ◽  
Chien Chen Diao ◽  
Yuan Tai Hsieh ◽  
Ping Shou Cheng
Keyword(s):  
Single Phase ◽  
High Dielectric Constant ◽  
Gate Dielectric ◽  
Raw Materials ◽  
Ceramic Materials ◽  
Dielectric Constants ◽  
Dielectric Characteristics ◽  
X Ray ◽  
High Dielectric ◽  
Ray Patterns

In this study, we hoped to find the single-phase high dielectric FET gate-used ceramic materials, which will be used in the sputtering method and have the dielectric constants higher than those of SiO2 and Si3N4. TiO2, La2O3 and ZrO2 are mixed with SiO2 to format the (1-x) TiO2-x SiO2, (1-x) ZrO2-x SiO2 and (1-x) La2O3-x SiO2 compositions, where x is dependent on the different raw materials. The all compositions are calcined at 1100oC and sintered at 1400oC~ 1550oC for 2hrs, and the X-ray patterns are used to find the crystal phases of all sintered ceramics. Because of the existence of single-phase, the sintering and dielectric characteristics of 0.3 La2O3-0.7 SiO2 ceramic are further developed.

Preparation and Characterization of LaAlO3 via Sol-Gel Process

2012 ◽  
Vol 624 ◽  
pp. 26-29 ◽  
Author(s):  
Xiao Yan Zhang ◽  
Teng Zhang ◽  
Xi Wei Qi ◽  
Jian Quan Qi ◽  
Gui Fang Sun ◽  
...  
Keyword(s):  
Citric Acid ◽  
Ph Value ◽  
Raw Materials ◽  
Sol Gel ◽  
Chelating Agent ◽  
Sem Analysis ◽  
Lanthanum Aluminate ◽  
Water As Solvent ◽  
Sol Gel Process ◽  
Scherrer Formula

Lanthanum aluminate powders were synthesized by sol-gel process with metal nitrates as raw materials, 2-methoxyethanol/water as solvent and citric acid as chelating agent. The influence of this techniques (the amount of citric acid, pH value, calcination temperature and the ratio of 2-methoxyethanol/water) on the lanthanum aluminate powders were studied. The XRD shows pure LaAlO3 powders could be obtained after calcining at 600-900 °C. The SEM analysis indicates that the LaAlO3 particles are uniform and nanosized with a range of about 40-70 nm, which is slightly larger than the estimated particle size using Scherrer formula.

Microstructural characterization of laser-melted/roller-quenched dicalcium silicate

1988 ◽  
Vol 46 ◽  
pp. 582-583
Author(s):  
C. J. Chan ◽  
K. R. Venkatachari ◽  
W. M. Kriven ◽  
J. F. Young
Keyword(s):  
Particle Size ◽  
Raw Materials ◽  
Shape Change ◽  
Microstructural Characterization ◽  
Particle Size Effect ◽  
Dicalcium Silicate ◽  
Laser Melting ◽  
Uniform Size ◽  
Cell Shape Change ◽  
Wide Range

Dicalcium silicate (Ca2SiO4) is a major component of Portland cement. It has also been investigated as a potential transformation toughener alternative to zirconia. It has five polymorphs: α, α'H, α'L, β and γ. Of interest is the β-to-γ transformation on cooling at about 490°C. This transformation, accompanied by a 12% volume increase and a 4.6° unit cell shape change, is analogous to the tetragonal-to-monoclinic transformation in zirconia. Due to the processing methods used, previous studies into the particle size effect were limited by a wide range of particle size distribution. In an attempt to obtain a more uniform size, a fast quench rate involving a laser-melting/roller-quenching technique was investigated.The laser-melting/roller-quenching experiment used precompacted bars of stoichiometric γ-Ca2SiO4 powder, which were synthesized from AR grade CaCO3 and SiO2xH2O. The raw materials were mixed by conventional ceramic processing techniques, and sintered at 1450°C. The dusted γ-Ca2SiO4 powder was uniaxially pressed into 0.4 cm x 0.4 cm x 4 cm bars under 34 MPa and cold isostatically pressed under 172 MPa. The γ-Ca2SiO4 bars were melted by a 10 KW-CO2 laser.

Gluten-Free Dry Mixtures with Rice and Amaranth for Children over Three Years Old with Gluten Intolerance

Food Industry ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 23-31
Author(s):  
Sergey Urubkov ◽  
Svetlana Khovanskaya ◽  
Ekaterina Pyrieva ◽  
Olga Georgieva ◽  
Stanislav Smirnov
Keyword(s):  
Celiac Disease ◽  
Treatment Effectiveness ◽  
Raw Materials ◽  
Calculated Data ◽  
Limited Range ◽  
Gluten Free ◽  
Fruit And Vegetable ◽  
Organoleptic Evaluation ◽  
Free Products ◽  
Wide Range

Diet therapy is one of the main approaches to the treatment of a wide range of diseases of the digestive system. The treatment effectiveness of celiac disease depends on how strictly the patient adheres to a gluten-free diet. It is often disrupted due to the limited range of recommended foods and dishes, especially for children who are particularly sensitive to dietary restrictions. In this case, the development of new types of specialized gluten-free products is relevant, allowing to expand the diet both in terms of nutritional value and taste diversity. This study concerns the recipe developments of dry gluten-free mixtures using rice and amaranth with the inclusion of fruit and vegetable and berry raw materials intended for the nutrition of children over three years old suffering from celiac disease. When developing the recipes, researchers used various combinations of rice and amaranth flour, as well as fruit and vegetable powders. The rice flour composition varied in the range from 15 to 75%; amaranth – from 15 to 45%; fruit and vegetable and berry powders – up to 10%. The finished product was gluten-free cookies, muffins, pancakes made of rice and amaranth. Organoleptic evaluation showed that the studied samples of gluten-free cookies have high quality characteristics, have a pleasant taste and aroma. According to the calculated data, specialized gluten-free dry mixtures intended for children over three years with celiac disease can serve as an important source of: vegetable carbohydrates – from 26.81 to 55.19 g / 100g of finished products; protein – from 4.06 to 11.82 g/100g of finished products; dietary fiber – from 3.82 to 6.36 g/100g of finished products; and energy – from 158.12 to 333.96 kcal/100g of finished products) The developed recipess of gluten-free products can help to provide children with an adequate amount of nutrients and energy.

Safety assessment of biological raw materials in the system of medicines quality assurance

2020 ◽  
pp. 63-72
Author(s):  
Yu. Olefir ◽  
E. Sakanyan ◽  
I. Osipova ◽  
V. Dobrynin ◽  
M. Smirnova ◽  
...  
Keyword(s):  
Raw Materials ◽  
State Level ◽  
The State ◽  
Spongiform Encephalopathy ◽  
Safety Standards ◽  
Wide Range ◽  
The Russian Federation ◽  
Key Aspects ◽  
First Time ◽  
Medicines Quality

The entry of a wide range of biotechnological products into the pharmaceutical market calls for rein-forcement of the quality, efficacy and safety standards at the state level. The following general monographs have been elaborated for the first time to be included into the State Pharmacopoeia of the Russian Federation, XIV edition: "Viral safety" and "Reduction of the risk of transmitting animal spongiform encephalopathy via medicinal products". These general monographs were elaborated taking into account the requirements of foreign pharmacopoeias and the WHO recommendations. The present paper summarises the key aspects of the monographs.

scholarly journals Bio-Based Alternatives to Phenol and Formaldehyde for the Production of Resins

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim
Keyword(s):  
Raw Materials ◽  
Phenol Formaldehyde ◽  
Raw Material ◽  
Wood Industry ◽  
Suitable Material ◽  
The Past ◽  
Wide Range ◽  
Recent Developments ◽  
Sustainable Materials ◽  
Materials Used

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.

scholarly journals Portable near Infrared Spectroscopy as a Tool for Fresh Tomato Quality Control Analysis in the Field

2021 ◽  
Vol 11 (7) ◽  
pp. 3209
Author(s):  
Karla R. Borba ◽  
Didem P. Aykas ◽  
Maria I. Milani ◽  
Luiz A. Colnago ◽  
Marcos D. Ferreira ◽  
...  
Keyword(s):  
Citric Acid ◽  
Near Infrared ◽  
Prediction Models ◽  
Quality Attributes ◽  
Internal Quality ◽  
Control Analysis ◽  
Tomato Quality ◽  
Wide Range ◽  
Different Types ◽  
Fresh Tomato

Portable spectrometers are promising tools that can be an alternative way, for various purposes, of analyzing food quality, such as monitoring in a few seconds the internal quality during fruit ripening in the field. A portable/handheld (palm-sized) near-infrared (NIR) spectrometer (Neospectra, Si-ware) with spectral range of 1295–2611 nm, equipped with a micro-electro-mechanical system (MEMs), was used to develop prediction models to evaluate tomato quality attributes non-destructively. Soluble solid content (SSC), fructose, glucose, titratable acidity (TA), ascorbic, and citric acid contents of different types of fresh tomatoes were analyzed with standard methods, and those values were correlated to spectral data by partial least squares regression (PLSR). Fresh tomato samples were obtained in 2018 and 2019 crops in commercial production, and four fruit types were evaluated: Roma, round, grape, and cherry tomatoes. The large variation in tomato types and having the fruits from distinct years resulted in a wide range in quality parameters enabling robust PLSR models. Results showed accurate prediction and good correlation (Rpred) for SSC = 0.87, glucose = 0.83, fructose = 0.87, ascorbic acid = 0.81, and citric acid = 0.86. Our results support the assertion that a handheld NIR spectrometer has a high potential to simultaneously determine several quality attributes of different types of tomatoes in a practical and fast way.

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