Crystallization of Amorphous Germanium in a Silver Germanium Layered System

Layered System ◽

In Situ Tem ◽

Heat Of Reaction ◽

Scanning Calorimetry ◽

Amorphous Germanium ◽

ABSTRACTWe studied crystallization of amorphous germanium (a-Ge) induced in a Ag/a-Ge layered system, using in situ transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). Amorphous Ge was found to crystallize at about 270°C with the heat of reaction of 10±lkJ/mol. In situ TEM revealed that Ag grains migrate into the a-Ge phase leaving the crystalline Ge (c-Ge) phase behind. From this observation, we propose a model whereby the Ag provides the fastest path for the Ge atoms to diffuse from a-Ge to c-Ge phases.

Reactions in Metal-Metalloid Multilayers

MRS Proceedings ◽

10.1557/proc-311-3 ◽

1993 ◽

Vol 311 ◽

Cited By ~ 3

Author(s):

Robert Sinclair ◽

Toyohiko J. Konno

Keyword(s):

Electron Microscopy ◽

Reactive Systems ◽

Nucleation And Growth ◽

In Situ Observation ◽

Scanning Calorimetry ◽

Compound Formation ◽

ABSTRACTWe have studied the reactions at metal-metalloid interfaces using high resolution transmission electron microscopy, including in situ observation, and differential scanning calorimetry. There is contrasting behavior depending on the affinity for interaction or segregation. For reactive systems, compound formation ultimately results, but this can be preceded by solidstate amorphization. For non-reactive systems, crystallization of the metalloid is often achieved with nucleation and growth mediated by the metal phase.

Crystallization of Amorphous Si In Al/Si Multilayers

MRS Proceedings ◽

10.1557/proc-230-189 ◽

1991 ◽

Vol 230 ◽

Cited By ~ 5

Author(s):

Toyohiko J. Konno ◽

Robert Sinclair

Keyword(s):

Electron Microscopy ◽

Layered Structure ◽

Heat Of Reaction ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

X Ray ◽

Transmission Electron ◽

Amorphous Si

AbstractThe crystallization of amorphous Si in a Al/Si multilayer (with a modulation length of about 120Å) was investigated using transmission electron microscopy, differential scanning calorimetry and X-ray diffraction. Amorphous Si was found to crystallize at about 175 °C with the heat of reaction of 11±2(kJ/mol). Al grains grow prior to the nucleation of crystalline Si. The crystalline Si was found to nucleate within the grown Al layers. The incipient crystalline Si initially grows within the Al layer and then spreads through the amorphous Si and other Al layers. Because of extensive intermixing, the original layered structure is destroyed. The Al(111) texture is also enhanced.

In-situ TEM annealing of amorphous Fe-24at.%W coatings and the effect of crystallization on hardness

Journal of Materials Science ◽

10.1007/s10853-020-05485-7 ◽

2020 ◽

Vol 56 (5) ◽

pp. 4006-4012

Author(s):

Antonio Mulone ◽

Inga Ennen ◽

Andreas Hütten ◽

Uta Klement

Keyword(s):

Electron Microscopy ◽

Amorphous Structure ◽

In Situ Tem ◽

Amorphous Coating ◽

Scanning Calorimetry ◽

Plating Bath ◽

Maximum Value ◽

AbstractThis paper describes the crystallization which occurs upon annealing of an amorphous Fe-24at.%W coatings, electrodeposited from a glycolate-citrate plating bath. A combination of Differential Scanning Calorimetry and in-situ Transmission Electron Microscopy annealing is used to study the onset of crystallization of the amorphous coating. The in-situ TEM analyses reveal the formation of first crystallites after annealing at 400 °C for 30 min. Upon a temperature increase to 500–600 °C, the crystallites develop into Fe-rich nanocrystals with ~ 40 nm grain size. The nanocrystals are dispersed in the remaining amorphous Fe-W matrix, which results in the formation of a mixed nanocrystalline-amorphous structure. The observed crystallization can be held responsible for the increase in the hardness obtained upon annealing of Fe-24at.%W coatings. In fact, the hardness of the as-deposited material increases from 11 to 13 GPa after annealing at 400 °C, and it reaches the maximum value of 16.5 GPa after annealing at 600 °C.

Low temperature transmission electron microscopy and differential scanning calorimetry characterization of latexes stabilized with surface active block oligomers

Polymer ◽

10.1016/0032-3861(92)90869-x ◽

1992 ◽

Vol 33 (10) ◽

pp. 2043-2050 ◽

Cited By ~ 8

Author(s):

Adriana Haas-Bar Iian ◽

Isao Noda ◽

Lee A. Schechtman ◽

Yeshayahu Talmon

Keyword(s):

Electron Microscopy ◽

Low Temperature ◽

Scanning Calorimetry ◽

Transmission Electron ◽

Surface Active ◽

Active Block

Low-temperature instability of Ti2SnC: A combined transmission electron microscopy, differential scanning calorimetry, and x-ray diffraction investigations

Journal of Materials Research ◽

10.1557/jmr.2009.0012 ◽

2009 ◽

Vol 24 (1) ◽

pp. 39-49 ◽

Cited By ~ 49

Author(s):

J. Zhang ◽

B. Liu ◽

J.Y. Wang ◽

Y.C. Zhou

Keyword(s):

Electron Microscopy ◽

Low Temperature ◽

X Ray Diffraction ◽

Scanning Calorimetry ◽

Temperature Instability ◽

X Ray ◽

Transmission Electron ◽

Ceramic Microstructure

Transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and x-ray diffraction (XRD) investigations were conducted on the hot-pressed Ti2SnC bulk ceramic. Microstructure features of bulk Ti2SnC ceramic were characterized by using TEM, and a needle-shaped β-Sn precipitation was observed inside Ti2SnC grains with the orientation relationship: (0001) Ti2SnC // (200) Sn and Ti2SnC // [001] Sn. With the combination of DSC and XRD analyses, the precipitation of metallic Sn was demonstrated to be a thermal stress-induced process during the cooling procedure. The reheating temperature, even as low as 400 °C, could trigger the precipitation of Sn from Ti2SnC, which indicated the low-temperature instability of Ti2SnC. A substoichiometry Ti2SnxC formed after depletion of Sn from ternary Ti2SnC phase. Under electron beam irradiation, metallic Sn was observed diffusing back into Ti2SnxC. Furthermore, a new Ti7SnC6 phase with the lattice constants of a = 0.32 and c = 4.1 nm was identified and added in the Ti-Sn-C ternary system.

Preparation and characterization of baicalein loaded phytosomes: Assessment of in vitro parameters

International Journal of PharmTech Research ◽

10.20902/jptr.2019.120404 ◽

2020 ◽

Vol 12 (4) ◽

pp. 22-29

Author(s):

KanchanV Zade ◽

Alok Pal Jain

Keyword(s):

Electron Microscopy ◽

Herbal Extracts ◽

Scanning Calorimetry ◽

Reverse Phase ◽

Tem Analysis ◽

Phytosome is a complex between natural active ingredient and a phospholipid. Further, phytosomes been applied to many popular herbal extracts or active molecules for augmenting oral dissolution. Therefore, in present investigation, orally administered Baicalein, atype of flavanoids, is poorly absorbed, and shows suboptimal dissolution. The phytosomes encapsulating baicalein (1:1 Mm) were prepared by reverse phase evaporation method followed by lyophilization. Transmission electron microscopy (TEM) analysis revealed that phytosomes were almost spherical in shape with particle size below 100 nm. The Powder ex-ray diffraction (PXRD) and differential scanning calorimetry (DSC) demonstrated that Baicalein loaded phytosomes were amorphous in nature. Amorphization of therapeutic moiety leads to improvement in dissolution. In conclusion, epigallocatechin loaded phytosomes exhibited promising results and warrant further in vitro andin vivo investigations under a set of stringent parameters for transforming in to a clinically viable products.

Combined effect of Sn addition and pre-ageing on natural secondary and artificial ageing of Al–Mg–Si alloys

Journal of Materials Science ◽

10.1007/s10853-021-06654-y ◽

2022 ◽

Author(s):

Xingpu Zhang ◽

Meng Liu ◽

Jiangwei Wang ◽

Jixue Li ◽

John Banhart

Keyword(s):

Electron Microscopy ◽

Electrical Resistivity ◽

Combined Effect ◽

Artificial Ageing ◽

Combined Effects ◽

Natural Ageing ◽

Scanning Calorimetry ◽

AbstractBoth Sn addition and pre-ageing are known to be effective in maintaining the artificial ageing potential after natural ageing of Al–Mg–Si alloys. In this study, the combined effects of Sn addition and pre-ageing at 100 °C or 180 °C on natural secondary ageing and subsequent artificial ageing of an alloy AA6014 were investigated using hardness, electrical resistivity, differential scanning calorimetry and transmission electron microscopy characterizations. It is found that pre-ageing can suppress natural secondary ageing and improve the artificial ageing hardening kinetics and response after 1 week of natural secondary ageing in both alloys with and without Sn addition. The effect of pre-ageing at 100 °C is more pronounced in the Sn-free alloy while the combination of pre-ageing at 180 °C and adding Sn shows superiority in suppressing natural secondary ageing and thus avoiding the undesired hardening before artificial ageing. Moreover, when natural ageing steps up to 8 h are applied before pre-ageing at 100 °C, the effect of pre-ageing in Sn-added alloy can be further improved. The influence of Sn on vacancies at different ageing temperatures is discussed to explain the observed phenomena. Graphical abstract

Clarifying the Role of Mg2Si and Si in Localized Corrosion of Aluminum Alloys by Quasi In Situ Transmission Electron Microscopy

CORROSION ◽

10.5006/3457 ◽

2020 ◽

Vol 76 (5) ◽

pp. 464-475 ◽

Cited By ~ 3

Author(s):

Shravan K. Kairy ◽

Nick Birbilis

Keyword(s):

Electron Microscopy ◽

Magnesium Silicide ◽

Localized Corrosion ◽

In Situ Tem ◽

Al Alloy ◽

Transmission Electron ◽

Al Matrix

The role of magnesium silicide (Mg2Si) and silicon (Si) particles in the localized corrosion of aluminum (Al) alloys was investigated herein. Sub-micrometer-sized Mg2Si and Si particles were grown in the Al matrix of Al-Mg-Si and Al-Si alloys, respectively, and characterized by transmission electron microscopy (TEM). A quasi in situ TEM technique was used to study an identical location containing Mg2Si or Si particle in the Al matrix, prior to and following a period of immersion in 0.1 M NaCl at pH 6, 2, and 12. At pH 6 and 2, Mg2Si was initially “anodic,” preferentially dealloying via selective dissolution of Mg, resulting in the development of SiO-rich remnants that are electrochemically inert. The SiO-rich remnants at pH 2 physically detached from the Al matrix. Silicon particles were electrochemically inert at pH 6, while “cathodic” at pH 2, dissolving the Al matrix at their periphery. It was observed that copper (Cu) was redeposited on Si particles at pH 2. At pH 12, Mg2Si and Si were “cathodic” to the Al matrix. This study clarifies, and provides new insights into, the characteristics of Al alloy physical manifestation of corrosion associated with Mg2Si and Si at the nanoscale.