Phase Evaluation of Pure Mg, Mg-1Ca and Mg-1Ca-3Zn ‎Alloys by Thermal Analysis Used in ‎Medical Applications

2014 ◽  
Vol 606 ◽  
pp. 93-97
Author(s):  
Hamid Reza Bakhsheshi-Rad ◽  
Esah Hamzah ◽  
M.H. Idris ◽  
S. Farahany ◽  
A. Fereidouni‎
Keyword(s):  
Thermal Analysis ◽  
Microstructural Analysis ◽  
Intermetallic Phase ◽  
Phase Identification ◽  
X Ray ◽  
Dendrite Coherency Point ◽  
Coherency Point ◽  
Phase Evaluation ◽  
Mg Melt ◽  
Significant Attention

In this research paper phase identification was conducted based on the thermal and microstructural analysis of pure Mg, binary ‎Mg-Ca and ternary Mg-Ca-Zn alloys which have been received significant attention to be used as biodegradable implants. ‎Thermal analysis results show that nucleation temperature of primary Mg decreased and solidification range expanded with ‎adding Ca and Zn to the Mg melt. Moreover, characteristics temperatures of intermetallic phase assess for Mg-1Ca and Mg-‎‎1Ca-3Zn alloys. Microstructural evolutions of specimens were characterized by optical microscopy, scanning electron ‎microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). The result revealed that the identification of Mg2Ca and Ca2Mg6Zn3‎intermetallic phases by thermal analysis which were also detected by EDS. Furthermore with addition of Ca and Zn elements, the ‎coherency time increased while, the fraction of primary α-Mg at dendrite coherency point (fαDCP) decreased.‎

Effects of Melt Treatment on Dendrite Coherency of A357 Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 3886-3890
Author(s):  
Zhong Wei Chen ◽  
Pei Chen ◽  
Li Fan
Keyword(s):  
Thermal Analysis ◽  
Growth Rate ◽  
Cooling Rate ◽  
Solid Fraction ◽  
Dendrite Growth ◽  
A357 Alloy ◽  
Dendrite Coherency Point ◽  
Melt Treatment ◽  
Coherency Point ◽  
Dendrite Coherency

The Dendrite Coherency Point (DCP) of A357 alloy was determined after different melt treatments by double thermocouples, and the coherency solid fraction (fscoh) was calculated by thermal analysis. The results of dendrite coherency properties show that fscoh values increase with increased cooling rate for A357 alloy. For A357 alloys, fscoh values increase after grain refined and melt superheat treatment. The coherency point was found to be dependent on not only the morphology of the dendrites but also the dendrite growth rate.

Formation of Lanthanum Hydroxide and Oxide via Precipitation

2008 ◽  
Vol 135 ◽  
pp. 23-26 ◽  
Author(s):  
So Jin Kim ◽  
Won Kyu Han ◽  
Sung Goon Kang ◽  
Min Su Han ◽  
Young Hun Cheong
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Room Temperature ◽  
Thermal Transformation ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Lanthanum Hydroxide ◽  
X Ray ◽  
Phase Evaluation ◽  
Scanning Electron

Lanthanum hydroxide and oxide were prepared by the precipitation method in an aqueous medium at room temperature. The precipitate was examined using thermal analysis, X-ray diffraction and Scanning Electron Microscopy to investigate the phase evaluation and the thermal transformation by decomposition. The as-precipitated powder from the precipitation method was hexagonal La(OH)3. The lanthanum hydroxide was decomposed to oxide in two-steps as La(OH)3 → LaOOH + H2O and 2LaOOH → La2O3 + H2O.

scholarly journals Analysis of Crystallisation Process of Cast Magnesium Alloys Based on Thermal Derivative Analysis / Analiza Procesu Krystalizacji Odlewniczych Stopów Magnezu W Oparciu O Analizę Termicznoderywacyjną

2015 ◽  
Vol 60 (4) ◽  
pp. 2993-3000 ◽  
Author(s):  
M. Król ◽  
T. Tański ◽  
G. Matula ◽  
P. Snopiński ◽  
A.E. Tomiczek
Keyword(s):  
Magnesium Alloys ◽  
Cooling Curve ◽  
X Ray ◽  
Dendrite Coherency Point ◽  
Derivative Analysis ◽  
Crystallisation Process ◽  
Cast Magnesium Alloys ◽  
Coherency Point ◽  
Dendrite Coherency ◽  
Cast Magnesium

The paper presents the results of the crystallisation process of cast magnesium alloys based on the thermal-derivation analysis. The effects of aluminium content and cooling rate on the characteristic parameters of the evaluation of magnesium dendrites during solidification at different cooling rates were investigated by thermal-derivative analysis (TDA). Dendrite coherency point (DCP) is defined with a new approach based on the second derivative cooling curve. Solidification behaviour was evaluated via one thermocouple thermal analysis method. Microstructural evaluations were characterised by light microscope, X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy. This research revealed that utilisation of d2T/dt2 versus the time curve methodology allows for analysis of the dendrite coherency point.

Effects of Microwave Processing on the Properties of Nickel Oxide/Zirconia/Ceria Composites

2014 ◽  
Vol 975 ◽  
pp. 154-159 ◽  
Author(s):  
Lucas Batochi Pinheiro ◽  
Antonio Eduardo Martinelli ◽  
Fabio Coral Fonseca
Keyword(s):  
Thermal Analysis ◽  
Electrical Properties ◽  
Phase Identification ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Assisted ◽  
Impregnation Technique ◽  
Thermal And Electrical Properties ◽  
Hydroxide Coprecipitation ◽  
Composite Samples

The effect of a microwave-assisted hydrothermal (MWH) treatment on the structural, thermal, and electrical properties of NiO/ZrO2:8 mol%Y2O3(YSZ)/CeO2 (60/20/20 wt.%) composite was investigated. Powders were synthesized by a hydroxide coprecipitation-impregnation technique, in which Ni and Ce oxides were coprecipitaed in a suspension containing YSZ. Simultaneous thermogravimetry and differential thermal analysis revealed that MWH treatment promotes the crystallization of coprecipitated phases. X-ray diffraction analysis was used for phase identification and the calculated lattice parameters indicated the formation of YSZ:CeO2 solid solution during sintering. Impedance spectroscopy measurements showed that the electrical properties of the composite samples were not significantly affected by the MHW.

A study of micropyretic reactions in the Mo–Si–Al ternary system

1997 ◽  
Vol 12 (6) ◽  
pp. 1481-1491 ◽  
Author(s):  
Ming Fu
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Ignition Temperature ◽  
Single Phase ◽  
Intermetallic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Additions ◽  
Scanning Electron

Micropyretic synthesis technique employs self-sustaining exothermic (combustion) reactions for the preparation of various ceramic, intermetallic, and composite materials. In the present work, the combustion reactions of Mo and Si with Al additions have been systematically studied. The atomic mixtures of the reactant powders are chosen to be Mo + (2 − x)Si + xAl with x = 0−0.4. In comparison with the Mo + 2Si reaction which leads to the formation of MoSi2, the substitution of Al for Si decreases the sample ignition temperature, but increases the intensity of the combustion reactions. In addition, the substitution of Al for Si results in the formation of a ternary intermetallic phase, called molybdenum alumino-silicide Mo(Si, Al)2, in the synthesized product. When the content of Al in the reactant mixtures reaches 0.4, nearly single phase Mo(Si, Al)2 is obtained and no MoSi2 is detected in the reaction product. These influences are analyzed by using x-ray diffraction (XRD), scanning electron microscopy (SEM), and differential thermal analysis (DTA). The effect of Al additions on the reaction mechanism is also discussed.

Phase identification in SiC whisker reinforced Al2O3-R2O3-based composites

1992 ◽  
Vol 50 (1) ◽  
pp. 152-153
Author(s):  
C.M. Sung ◽  
K.J. Ostreicher ◽  
M.L. Huckabee ◽  
S.T. Buljan
Keyword(s):  
Analytical Electron Microscopy ◽  
Phase Identification ◽  
Reinforced Composites ◽  
Ion Milling ◽  
X Ray ◽  
Binary Oxides ◽  
Analytical Electron ◽  
The Matrix ◽  
Second Phases ◽  
Convergent Beam

A series of binary oxides and SiC whisker reinforced composites both having a matrix composed of an α-(Al, R)2O3 solid solution (R: rare earth) have been studied by analytical electron microscopy (AEM). The mechanical properties of the composites as well as crystal structure, composition, and defects of both second phases and the matrix were investigated. The formation of various second phases, e.g. garnet, β-Alumina, or perovskite structures in the binary Al2O3-R2O3 and the ternary Al2O3-R2O3-SiC(w) systems are discussed.Sections of the materials having thicknesses of 100 μm - 300 μm were first diamond core drilled. The discs were then polished and dimpled. The final step was ion milling with Ar+ until breakthrough occurred. Samples prepared in this manner were then analyzed using the Philips EM400T AEM. The low-Z energy dispersive X-ray spectroscopy (EDXS) data were obtained and correlated with convergent beam electron diffraction (CBED) patterns to identify phase compositions and structures. The following EDXS parameters were maintained in the analyzed areas: accelerating voltage of 120 keV, sample tilt of 12° and 20% dead time.

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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