scholarly journals Simultaneous Differential Thermal Analysis and Thermogravimetric Analysis of Si-30B Alloy

2020 ◽  
Vol 29 (11) ◽  
pp. 7073-7079
Author(s):  
M. Homa ◽  
N. Sobczak ◽  
K. Hodor ◽  
S. Gezgin
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Eutectic System ◽  
Critical Temperatures ◽  
X Ray ◽  
Gas Atmosphere ◽  
Temperature Interaction ◽  
Dta Curve

AbstractThis article focuses on the experimental determination of the transformation temperature of Si-30B alloy in the temperature range of 25-1820 °C in a flowing gas atmosphere (He, 99.9992%) carried out by simultaneous differential thermal analysis and thermogravimetric analysis (DTA–TG) using a graphite container. The DTA curve during heating showed the presence of two critical temperatures, i.e., T = 1380.7 °C and T = 1532.0 °C. The first one corresponds to the melting point of a eutectic system (Si + SiB6). The high-temperature interaction and reactivity between the alloy and the container during DTA–TG test were evaluated by scanning electron microscopy coupled with energy-dispersive x-ray analysis. The results have demonstrated that the graphite container reacts with both liquid silicon and boron dissolved in liquid constituent of the alloy to form SiC and B4C, respectively.

ADSORPTION OF CYCLOHEXANE AND BENZENE ON MIXED HYDROXIDES AND OXIDES OF MAGNESIUM AND ALUMINIUM

1966 ◽  
Vol 44 (8) ◽  
pp. 877-884 ◽  
Author(s):  
R. I. Razouk ◽  
Sh. Nashed ◽  
F. N. Antonious
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Surface Area ◽  
Structural Changes ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
Oxide Systems ◽  
X Ray ◽  
Characteristic Lines

Seven mixed hydroxides of magnesium and aluminium were prepared, and phase and structural changes accompanying their dehydration were investigated by differential thermal analysis, thermogravimetric analysis, and X-ray diffraction techniques. The differential thermal analysis curves possess 2 peaks corresponding to those of parent hydroxides together with a new peak, and the thermogravimetric analysis curves show slight inflections. X-ray diffraction patterns of the mixed hydroxides possess the characteristic lines of the parent hydroxides together with three to five new intense lines which might indicate the formation of a double hydroxide. When the mixed hydroxides are progressively heated they give rise to products possessing patterns which first become diffuse and ultimately pass mainly into the spinel pattern.Adsorption isotherms of cyclohexane and benzene were measured on the mixed hydroxides and their dehydration products. Specific surface areas calculated by the application of the Brunauer, Emmett, Teller (B.E.T.) equation are in general in good agreement for the two adsorbates. The surface area increases with rise of dehydration temperature to a maximum at 500–600 °C and then decreases with further rise in temperature. This behavior is common to crystalline oxide systems and may be ascribed to the intermingling of decomposition, re-crystallization, and sintering processes. Variations in the molecular ratio of the mixed oxides (as much as 20-fold), and in the method of preparation, do not much alter the surface area.

Dehydration processes in borate minerals: pentahydroborite and nifontovite from Fuka Mine, Okayama Prefecture, Japan

2010 ◽  
Vol 74 (6) ◽  
pp. 1013-1025 ◽  
Author(s):  
V. Bermanec ◽  
N. Tomašić ◽  
Ž. Žigovečki Gobac ◽  
M. Rajić Linarić ◽  
K. Furić
Keyword(s):  
Thermal Analysis ◽  
Raman Spectroscopy ◽  
Differential Thermal Analysis ◽  
Calcium Borate ◽  
X Ray Diffraction ◽  
Critical Temperatures ◽  
X Ray ◽  
Borate Minerals ◽  
Dehydration Processes ◽  
Okayama Prefecture

AbstractData on the dehydration of pentahydroborite, CaB2O(OH)6·2H2O and nifontovite, Ca3B6O6(OH)12·2H2O from the Fuka mine, Japan are presented. Critical temperatures of the dehydration of the borates were determined by thermogravimetric analysis/differential thermal analysis measurements. The untreated mineral samples and their heating products were investigated by X-ray diffraction and Raman spectroscopy. Upon dehydration, both minerals decompose and undergo amorphization, and at greater temperatures crystallize as an orthorhombic calcium borate, CaB2O4 (Pnca). The dehydration paths of the two minerals are different, with nifontovite showing a greater resistance to decomposition and amorphization than pentahydroborite. Differences in the dehydration processes are related to the residuals of the water content and structural accommodation of the borate polyanion.

scholarly journals Determination of the Order of Kinetics of a DTA Curve by Using the Concept of Skewness

2020 ◽  
Vol 36 (6) ◽  
pp. 1235-1239
Author(s):  
BIKASH KUMAR SARKAR ◽  
INDRANIL BHATTACHARYYA ◽  
ANANDA SARKAR ◽  
PARTHA SARATHI MAJUMDAR
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
First Order ◽  
Positive Skewness ◽  
Order Of Kinetics ◽  
Negative Skewness ◽  
Dta Curves ◽  
Dta Curve ◽  
Kinetics Of

In the present paper, a novel way of finding out the order of kinetics of differential thermal analysis (DTA) curves by using the concept of skewness (Sk) has been investigated. It is found that for a particular DTA peak, skewness is a function of both the order of kinetics and the quantity, First order DTA peaks are characterized by negative skewness whereas those for the second order are characterized by positive skewness. Therefore, skewness can be used as an indicator of the order of kinetics of a DTA peak. We have evaluated and compared the orders of kinetics of some reported DTA peaks using the concept of skewness and found that the resulting values of the orders of kinetics are in fair agreement with those reported in literature.

The Effect of H3BO3 Microaddition on Microstructure of Ni/MgO Sintered Compact by Co-Precipitation Method

2013 ◽  
Vol 750 ◽  
pp. 168-171
Author(s):  
Ning Ning Zhou ◽  
Dong Ying Ju ◽  
Wan Yu Ding
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Sintered Compact ◽  
X Ray ◽  
Sintered Powder ◽  
Co2 Flow ◽  
Co Precipitation

In the present work, Ni/MgO powder was prepared by co-precipitation in which CO restore NiO to elemental subtance Ni due to C2O42- was decompose to CO and CO2 at 700°C. As the process of the second sintering, H3BO3 was added into the sintered powder of 700°C and was grinded. Then the powder of H3BO3 added was sintered at 800°C，so that the powder was refined, obviously. Thermogravimetric analysis (TGA) and differential thermal analysis(DTA) was carried out in CO2 flow at 10°C/min. X-ray diffraction (XRD) was carried out on a X-ray diffractometer operated at 20KV and 40mA. The microstructures and morphologies were studied by EPMA and XPS.

Accurate Determination of γ′ Solvus in Ni-Al-X Ternary Systems

1988 ◽  
Vol 133 ◽  
Author(s):  
Yong Myong Hong ◽  
Yoshinao Mishima ◽  
Tomoo Suzuki
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Ternary System ◽  
Phase Relation ◽  
Accurate Determination ◽  
Ternary Systems ◽  
Phase Boundaries ◽  
X Ray ◽  
Phase Fields

ABSTRACTAn attempt has been made to determine the γ/γ′ phase boundaries with particular emphasis on the γ′ solvus in ternary Ni-Al-X systems with X being one of the VA or VIA transition metal elements. It is shown that the γ′ solvus in each ternary system can be obtained as a surface with respect to composition and temperature by employing differential thermal analysis (DTA) as a key experimental technique with support from energy dispersive X-ray spectroscopy combined with scanning elecron microscope(SEM-EDX). Also shown is that the DTA results often provide useful information on the phase relation in the vicinity of γ and γ′ phase fields. In the Ni-Al-V ternary system, for example, the pseudo-binary constitution between Ni3Al and Ni3V is suggested. The results presented here are systematic and consistent and therefore are reliable as compared with the previous results reported fragmentarily.

scholarly journals The products of selenite hydrothermal treatment in lithium chloride solutions

2000 ◽  
Vol 65 (4) ◽  
pp. 265-274
Author(s):  
Slobodanka Marinkovic ◽  
Aleksandra Kostic-Pulek ◽  
Mirjana Djuricic
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Microscopic Examination ◽  
Atmospheric Pressure ◽  
Calcium Sulphate ◽  
Infrared Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Sulphate Hemihydrate

Selenite was boiled in LiCl solutions of different concentrations (1 M, 2 M, 3 M, 4 M and 5M) at the respective boiling temperatures and atmospheric pressure. The products were subjected to X-ray diffraction analysis, qualitative infrared analysis, differential thermal analysis, thermogravimetric analysis and microscopic examination. The product obtained in the 1 M LiCl solution was the ?-form of calcium sulphate hemihydrate (?-CaSO4.0.5H2O). In more concentrated LiCl solutons, 2M and 3 M, the ?-form of calcium sulphate hemihydrate (?-CaSO4.0.5H2O) was formed. The product obtained in the 4MLiCl solution was also the ?-form of calcium sulphate hemihydrate, only mixed with the ?-form of calcium sulphate (?-CaSO4). Finally, in the 5 M LiCl solution the ?-form of calcium sulphate or ?-anhydrite was formed.

scholarly journals Characterisation of the Mural Paintings from the Misericordia Church of Odemira (Portugal)

2008 ◽  
Vol 587-588 ◽  
pp. 1019-1023
Author(s):  
Sara Valadas ◽  
Deolinda Tavares ◽  
João Coroado ◽  
António Santos Silva ◽  
Jorge Pedro ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Chemical Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mural Paintings ◽  
Microchemical Analysis ◽  
Lime Mortars ◽  
Local Sources

Several mortars from mural paintings were collected from the Misericórdia Church of Odemira and analysed by using different techniques namely X-ray diffraction, thermogravimetric analysis with differential thermal analysis, SEM-EDX, optical microscopy, CHNS elemental analysis and chemical analysis. Microfragments of paint layers were collected and analysed by microchemical analysis. The results showed that the mortars are aerial lime mortars with siliceous aggregates and that the pigments used were mainly pigments from local sources (red and yellow ochre’s and malachite) and small blue.

Identification and Thermal Stability of Copper(I) Sulfate

1972 ◽  
Vol 50 (23) ◽  
pp. 3872-3875 ◽  
Author(s):  
Kim Vo Van ◽  
Fathi Habashi
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Diffraction Pattern ◽  
Chemical Processes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

Anhydrous CU2SO4 was prepared and its X-ray diffraction pattern was established. Differential thermal analysis, thermogravimetric analysis, and X-ray diffraction methods were used to study the effect of heating in different atmospheres. The formation of CU2SO4 as an intermediate in chemical processes has been discussed.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

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