scholarly journals Processing and characterization of CaTiO3 perovskite ceramics

2014 ◽  
Vol 8 (2) ◽  
pp. 53-57 ◽  
Author(s):  
Guilherme Gralik ◽  
Alessandra Thomsen ◽  
Cristian Moraes ◽  
Fabiano Raupp-Pereira ◽  
Dachamir Hotza
Keyword(s):  
Calcium Titanate ◽  
Thermal Shrinkage ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
Insulating Materials ◽  
X Ray ◽  
Molar Ratios ◽  
Treatment Conditions ◽  
Semiconducting Ceramics

Calcium titanate (CaTiO3) ceramics with perovskite structure were produced by solid state reaction. Calcium carbonate (CaCO3) and titanium dioxide (TiO2) were mixed (in molar ratios 1/1 and 3/2), and the obtained mixtures were calcined at 1150 ?C in successive thermal cycles. The obtained samples were characterized by differential thermal analysis, thermogravimetry, X-ray diffraction, measurement of particle size distribution and linear thermal shrinkage. XRD results indicated that the samples have perovskite CaTiO3 structure with small amount of secondary CaO and TiO2 phases, and their phase composition depends on the heat treatment conditions. The measured values of electrical resistivity were within the characteristic range of insulating materials and approach values corresponding to semiconducting ceramics.

Synthesis and Characterization of Nano-Calcium Titanate-Based Coated Aluminum Oxide and its Application in Water Analysis of Cr(III) and Cr(VI) Concentration

2010 ◽  
Vol 44-47 ◽  
pp. 2136-2139
Author(s):  
Dong Zhang
Keyword(s):  
Aluminum Oxide ◽  
Sol Gel ◽  
Calcium Titanate ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Composite Adsorbent ◽  
X Ray ◽  
Ph Values ◽  
Adsorption Capability

Nano-calcium titanate-based coated aluminum oxide (ACCTO) was successfully prepared by the citrate acid sol-gel method and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Its application in speciation of Cr(III) and Cr(VI) from water was studied. The conditions of adsorption and elution were investigated. The results show that nanometer calcium titanate could be immobilized on the aluminum oxide firmly, becoming a composite adsorbent. Two forms of chromium showed different adsorption capability at different pH values, Cr (III) selectively retained at pH 8-14, whereas Cr (VI) retained at pH≤2. So separation of the Cr(III) and Cr(VI) is possible. Retained species were eluted with 5mL of 1 mol•L-1 HCl and NaOH. The Cr(III) and Cr(VI) concentration was measured by atomic absorption spectroscopy. The adsorption agent has a promising prospect in removal or enriching and separation of Cr(III) and Cr(VI) in water.

Synthesis and Characterization of Srilankite Nanowires

2008 ◽  
Vol 8 (3) ◽  
pp. 1481-1488 ◽  
Author(s):  
Marguerite Germain ◽  
Philip Fraundorf ◽  
Sam Lin ◽  
Elena A. Guliants ◽  
Christopher E. Bunker ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Superlattice Structure ◽  
Titanate Nanowires ◽  
Alkaline Conditions ◽  
Diffraction Patterns

We describe the synthesis and characterization of srilankite (Ti2ZrO6) nanowires. The nanowires are produced via hydrothermal synthesis with a TiO2/ZrO2 mixture under alkaline conditions. The zirconium titanate nanowires have median diameters of 60 nm and median lengths of 800 nm with the 〈022〉 axis along the length of the nanowire. Electron microscopy, energy dispersive X-ray spectroscopy, powder X-ray diffraction, and electron diffraction are used to characterize the phases and compare nanowires produced with varying molar ratios of Ti and Zr. Electron diffraction patterns produced from single nanowires show highly crystalline nanowires displaying a compositional-ordering superlattice structure with Zr concentrated in bands within the crystal structure. This is in contrast to naturally occurring bulk srilankite where Zr and Ti are randomly substituted within the crystal lattice. Streaking is observed in the electron diffraction patterns suggesting short-range ordering within the superlattice structure.

Microstructure and Growth Mechanism of Glucose-Carburized Nickel Substrates

2013 ◽  
Vol 716 ◽  
pp. 153-158
Author(s):  
E.M. Pechlivani ◽  
G. Stergioudis ◽  
E. Pavlidou ◽  
S. Skolianos ◽  
D. Tsipas
Keyword(s):  
Electrochemical Corrosion ◽  
Corrosion Current ◽  
Temperature Treatment ◽  
Effect Of Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treatment Conditions ◽  
Nickel Substrates ◽  
Current Densities

In this research, efforts were made to study the modification of microstructure of pure Ni matrices. Modification was attempted using glucose as carburizing medium under a control of heat treatment conditions. Nickel plates were carburized under vacuum conditions at 380°C and 650°C for 3 hours. In order to determine the parameters of the carburizing, thermal properties of glucose along with the thermochemical behavior were examined by Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA). The characterization of the microstructure of the carburized specimens was investigated by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). For analyzing the effect of temperature treatment on corrosion resistance, electrochemical corrosion tests were conducted. It was observed that the polarization curves for carburized samples at 380°C were shifted to lower corrosion current densities. Consequently, lower corrosion rates were achieved for these samples preventing the formation of extensive corrosion over their surfaces comparing with carburized Nickel substrates at 650°C.

Nucleation, Crystallization and Characterization of Mica-Based Glass-Ceramics with Fluorapatite

2014 ◽  
Vol 936 ◽  
pp. 164-169 ◽  
Author(s):  
Jia Bai ◽  
Duangrudee Chaysuwan
Keyword(s):  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Soaking Time ◽  
X Ray ◽  
Optimal Heat Treatment ◽  
Treatment Conditions ◽  
Quenched Glass ◽  
Dental Applications ◽  
Soaking Temperature

The glass system of SiO2-Al2O3-MgO-MgF2-SrCO3-CaCO3-CaF2-P2O5 was used to prepare machinable glass-ceramics for restorative dental applications. The aim of this study was to apply various heat treatments to produce mica-based glass-ceramics. Differential Thermal Analysis (DTA) was used to determine the optimal heat treatment conditions for nucleation and growth of the crystalline phases in the quenched glass. It was found that the optimum nucleation temperatures for the first and the second crystallization temperatures (Tp1 and Tp2) were 642°C and 635°C, respectively, and the optimum nucleation times were between 2 and 4 hours. X-Ray Diffraction (XRD) showed the phases developed were anorthite, calcium-mica, fluorapatite, strontium apatite, forsterite, fluorite and stishovite phases. The microstructures of glass-ceramics were observed by Scanning electron microscope (SEM), found to exhibit plate-like mica crystals with high interlocking and randomly oriented with a higher soaking temperature and prolongation of the soaking time for crystallization.

Characterization of p-type 4H-SiC epitaxial layer grown on (11-20) substrate

2001 ◽  
Vol 680 ◽  
Author(s):  
Kazutoishi Kojima ◽  
Toshiyuki Ohno ◽  
Mituhiro Kushibe ◽  
Koh Masahara ◽  
Yuuki Ishida ◽  
...  
Keyword(s):  
Boron Concentration ◽  
Hole Mobility ◽  
Crystalline Quality ◽  
Diffraction Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hall Effect Measurements ◽  
P Type ◽  
Incorporation Efficiency

ABSTRACTGrowth and characterization of p-type 4H-SiC epitaxial layers grown on (11-20) substrates are reported. P-type 4H-SiC epilayers with smooth surface morphology have been grown on (11-20) substrates by low-pressure, hot-wall type CVD with SiH4–C3H8–H2–TMA system. The doping concentration can be controlled in the range from about 1×1016cm−3 to 1×1019cm−3. Anisotropy of the crystalline quality is observed by x-ray diffraction measurement. P-type epilayers, in which near band-gap emissions are dominated and D-A pair peak is not observed, are obtained. Hole mobility of (11-20) epilayers is smaller than that of (0001) epilayers probably due to the lack of crystalline quality compared to (0001) epilayers. The results of both low-temperature photoluminescence and the temperature dependence of Hall effect measurements indicate that the boron concentration as undoped impurity in (11-20) epilayer is lower than that of (0001) epilayer. This may be caused by the smaller incorporation efficiency of boron into (11-20) epilayer than that of (0001) epilayer.

Preparation and Characterization of Nanometer Calcium Titanate Immobilized on Aluminum Oxide and its Adsorption Capacity for Heavy Metal Ions in Water

2010 ◽  
Vol 152-153 ◽  
pp. 670-673 ◽  
Author(s):  
Dong Zhang
Keyword(s):  
Aluminum Oxide ◽  
Heavy Metal Ions ◽  
Sol Gel ◽  
Calcium Titanate ◽  
X Ray Diffraction ◽  
Composite Adsorbent ◽  
X Ray ◽  
Adsorption Capacities ◽  
Adsorption Capability

Nanometer calcium titanate immobilized on Aluminum oxide (ACTO) was successfully prepared by the citrate acid sol-gel method and characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The adsorption capability of ACTO for Pb2+, Cd2+and Zn2+ from water was studied. Adsorption and elution were investigated under different conditions. The results show that nanometer calcium titanate could be immobilized on the aluminum oxide firmly, becoming a composite adsorbent. The Pb2+, Cd2+and Zn2+ were retained at pH 5-9, their adsorption capacities of ACTO were 124 mg•g-1, 8.58 mg•g-1 and 13.86 mg•g-1, respectively. The adsorption agent can be regenerated by elution with 2 mol•L-1 HNO3. The adsorbent has a promising prospect in removal or enriching and separation of heavy metals in water.

Thermal Characterization of Neodymium-Barium-Copper Ceramic (NBCo Ceramic) Synthesized from Barium Carbonate

2016 ◽  
Vol 869 ◽  
pp. 74-78
Author(s):  
José Passos Fernandes ◽  
A. Tibola ◽  
M. Lorensetti ◽  
G.W. Duarte ◽  
M.R. Rocha ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Barium Carbonate ◽  
Thermal Characterization ◽  
Neodymium Oxide ◽  
Differential Scanning Calorimetric ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treatment Conditions ◽  
Barium Copper

This work presents a study about thermal properties of a ceramic material based on NdBaCu system sintered with barium carbonate. These specialized ceramics are manufactured under special conditions and due to its unique electrical and thermal properties are frequently used by the electronic industry. Ceramics containing neodymium-barium-copper (NdBaCu) exhibit high conductivity at low temperatures. In this work, the ceramic samples were sintered with different percentage of barium carbonate, cupric and neodymium oxide and were characterized with Termogravimetric Analysis (TGA), Differential Scanning Calorimetric (DSC), Thermal Dilatometric Analysis (TDA) and X-Ray Diffraction Analysis (DRX). The results showed that the electrical conductivity of NdBaCu system is dependent on the calcination temperature. In turn, the complete calcination is dependent on the barium percentage and the thermal treatment conditions.

Preparation and Characterization of Nano-Calcium Titanate-Based Coated Silica Gel G and the Application in Adsorption of Heavy Metals

2010 ◽  
Vol 26-28 ◽  
pp. 835-838 ◽  
Author(s):  
Dong Zhang ◽  
Zhi Jiang Liu
Keyword(s):  
Heavy Metals ◽  
Silica Gel ◽  
Sol Gel ◽  
Calcium Titanate ◽  
X Ray Diffraction ◽  
Composite Adsorbent ◽  
Nickel Ions ◽  
X Ray ◽  
Adsorption Capacities

Nano-calcium titanate-based coated silica gel G (GCTO) was prepared by the citric acid sol–gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrophotometry (FTIR). Its lead, cadmium and nickel ions adsorption properties from water were studied. Adsorption and elution were investigated under different conditions. The results showed that the nanometer calcium titanate was immobilized on the silica gel G firmly, becoming a new composite adsorbent. The lead, cadmium and nickel ions were quantitatively retained at pH 5-9; their adsorption capacities of GCTO were 114 mg•g－1, 11.2 mg•g－1 and 20.1 mg•g－1, respectively. The adsorbent can be regenerated completely by elution with 1 mol•L－1 HNO3. The adsorbent has a promising prospect in removal or enriching and separation of heavy metals in water.

scholarly journals Synthesis and Characterization of Dodecylbenzene Sulfonic Acid doped Tetraaniline via Emulsion Polymerization

2012 ◽  
Vol 9 (3) ◽  
pp. 1342-1346 ◽  
Author(s):  
K. Basavaiah ◽  
K. Tirumala Rao ◽  
A. V. Prasada Rao
Keyword(s):  
Sulfonic Acid ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Molar Ratios ◽  
Uv Visible ◽  
Dodecylbenzene Sulfonic Acid ◽  
Diffraction Patterns ◽  
Thermal Stability Of

In this work, we report preparation and characterization of dodecylbenzene sulfonic acid (DBSA) doped tetraaniline via micelles assisted method using ammonium per sulphate (APS) as an oxidant. Here, DBSA act as dopant as well as template for tetraaniline nanostructures. The synthesized DBSA doped tetraaniline have been well characterized by X-ray diffraction patterns, Fourier transform infrared spectroscopy, UV-Visible spectroscopy, Scanning electron microscopy and thermogravimetry. The morphologies of tetraaniline were found to be dependent on molar ratios of N-phenyl-1, 4-phenylenediamine to DBSA. The spectroscopic data indicated that DBSA doped tetraaniline. Thermogravimetry studies revealed that the DBSA doping improved the thermal stability of tetraaniline.

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