scholarly journals Dissolution of Ordered Precipitates under ion Irradiation

1994 ◽  
Vol 373 ◽  
Author(s):  
Eric Camus ◽  
Françise Bourdeau ◽  
Christian Abromeit ◽  
Nelja Wanderka ◽  
Heinrich Wollenberger
Keyword(s):  
Electron Microscopy ◽  
Low Temperatures ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Atom Probe ◽  
Precipitate Dissolution ◽  
The Matrix ◽  
Ion Microscopy ◽  
The Stability ◽  
Atomic Mixing

AbstractThe stability of the ordered γʹ precipitates under 300-keV Ni+ irradiation was investigated between room temperature and 623 K. The two competing mechanisms of destabilization by cascade producing irradiation, i. e. disordering and dissolution of the γʹ precipitates in Nimonic PE16 alloy, has been studied separately by electron microscopy and field-ion microscopy with atom probe. At high temperatures, the precipitates are stable. At intermediate temperatures, the precipitates dissolve by ballistic mixing into the matrix, but the interface is restored by the radiation-enhanced atomic jumps. The order in the precipitates remains stable. At low temperatures, the precipitates are dissolved by atomic mixing. The dissolution proceeds in a diffusional manner with a diffusion coefficient normalized by the displacement rate D/K = 0.75 nm2dpa−1. The precipitates become disordered by a fluence of 0.1 dpa, whereas precipitate dissolution needs much higher fluences.

Dissolution of Copper Precipitates in An Fe−1·3Wt%Cu Alloy Under Fe+ Ion Irradiation

1998 ◽  
Vol 540 ◽  
Author(s):  
A. C. Nicol ◽  
M. L. Jenkins ◽  
N. Wanderka ◽  
C. Abromeit
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Room Temperature ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Resolution Electron ◽  
The Stability

AbstractThe stability of Cu precipitates in an Fe-1.3wt%Cu alloy under 300 keV Fe+ion irradiation has been investigated using transmission electron microscopy and high-resolution electron microscopy. The irradiations were carried out between room temperature and 550°C at displacement rates of 103 to 10−2 dpa(s)−1 to fluences of up to 30 dpa. Copper precipitates were found to keep their shape but decrease in size under all irradiation conditions. The results are discussed within the framework of a competitive process between irradiation induced ballistic destruction of precipitates by cascades and irradiation-enhanced precipitation.

scholarly journals A Study of the Phase Decomposition of Fe-Ni-Al-Mo Alloys

1990 ◽  
Vol 186 ◽  
Author(s):  
M.K. Miller ◽  
M.G. Hetherington ◽  
J.R. Weertman ◽  
H.A. Calderon
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Lattice Parameter ◽  
Al Alloys ◽  
Phase Decomposition ◽  
Probe Field ◽  
Transmission Electron ◽  
The Matrix ◽  
Ion Microscopy

AbstractThe aging of β′ NiAl precipitates in ferritic Fe-Ni-Al alloys has been studied by transmission electron microscopy (TEM) and atom-probe field-ion microscopy (APFIM). The addition of Mo alters the lattice parameter of the phases and segregation of Mo to the interface between the matrix and the particles may alter the interfacial energy. The compositions of the matrix, precipitates and interfaces have been measured by TEM and APFIM. The results are compared.

Identification of Nd163 phase in melt-textured NdBa2Cu3O7−δ bulk samples

2003 ◽  
Vol 18 (9) ◽  
pp. 2050-2054 ◽  
Author(s):  
Marcello Gombos ◽  
Vicente Gomis ◽  
Anna Esther Carrillo ◽  
Antonio Vecchione ◽  
Sandro Pace ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Optical Microscopy ◽  
Room Temperature ◽  
Polarized Light ◽  
Energy Dispersive ◽  
X Ray ◽  
Spontaneous Formation ◽  
The Stability ◽  
Scanning Electron

In this work, we report on the observation of Nd1Ba6Cu3O10,5 (Nd163) phase of the NdBaCuO system in melt-textured Nd123 bulk samples grown from a mixture of Nd123 and Nd210 phase powders. The observation was performed with polarized light optical microscopy and scanning electron microscopy–energy dispersive x-ray analyses. Images of the identified phase crystals show an aspect quite different from Nd422 crystals. Unexpectedly, Nd163 was individuated, even in “pure” Nd123 samples. Moreover, after long exposure to air, Nd163 disappeared completely in samples synthesized from powders containing Nd210. Thermogravimetry analyses of powders show that the stability of this phase in air is limited to temperatures higher than 900 °C, so Nd163 is unstable and highly reactive at room temperature. Moreover, an explanation of the observation of Nd163 in Nd210 free samples, based on the spontaneous formation of Nd163 phase in a Nd123 melt, is proposed.

scholarly journals Carbon Nanofibers from Carbon Nanotubes by 1.2 keVAr+Sputtering at Room Temperature

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Shuang-Xi Xue ◽  
Qin-Tao Li ◽  
Xian-Rui Zhao ◽  
Qin-Yi Shi ◽  
Zhi-Gang Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Carbon Nanofibers ◽  
Carbon Nanoparticles ◽  
Room Temperature ◽  
Ion Irradiation ◽  
Transmission Electron ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Carbon Nanowires

Multi-walled carbon nanotubes (MWCNTs) were irradiated by 1.2 keV Ar ion beams for 15–60 min at room temperature with current density of 60 µA/cm2. The morphology and microstructure are investigated by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The results show that carbon nanofibers are achieved after 60 min ion irradiation and the formation of carbon nanofibers proceeds through four periods, carbon nanotubes—amorphous carbon nanowires—carbon nanoparticles along the tube axis—conical protrusions on the nanoparticles surface—carbon nanofibers from the conical protrusions.

3Y-TZP/Si2N2O Composite Obtained by Pressureless Sintering

2008 ◽  
Vol 591-593 ◽  
pp. 415-422
Author(s):  
Carlos A. Xavier Santos ◽  
Motozo Hayakawa ◽  
José Carlos Bressiani
Keyword(s):  
Room Temperature ◽  
Bending Strength ◽  
Sintered Material ◽  
Silicon Oxynitride ◽  
Atmospheric Conditions ◽  
Sintering Aids ◽  
Pressure System ◽  
The Matrix ◽  
Considerable Resistance ◽  
The Stability

Y-TZP presents excellent properties at room temperature but these properties decrease as the temperature increases. This paper studies the behavior 20vol%Si3N4-SiC when added in YTZP matrix and heated under no pressure system. Al2O3 and Y2O3 were used to maintain the stability of the matrix and as sintering aids. The addition of Si3N4 and SiC in a Y-TZP matrix leads to formation of silicon oxynitride and it increases the mechanical properties like toughness and hardness. The mixture was milled and molded by CIP. Samples were heated at 1500°C, 1600°C and 1700°C for 2h without pressure under atmospheric conditions in bed-powders of Si3N4. Samples were characterized by XRD. Density, hardness, toughness, bending strength were measured. The structure of the material was observed in SEM/EPMA to verify the distribution of the materials in the composite. The formation of Si2N2O was observed in the sintered material and it showed an increment of both hardness and toughness as temperature increases. The samples presented considerable resistance of oxidation at 1000°C.

scholarly journals Isothiazolinones Quantification in Shampoo Matrices: A Matter of Method Optimization or Stability Driven by Interactions?

Cosmetics ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 4
Author(s):  
Mariana Tomás ◽  
Ana Sofia Agonia ◽  
Lígia Borges ◽  
Ana Palmeira de Oliveira ◽  
Rita Palmeira de Oliveira
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Extraction Procedure ◽  
Magnesium Silicate ◽  
Array Detector ◽  
Diode Array Detector ◽  
The Matrix ◽  
Method Optimization ◽  
Formulation Factors ◽  
The Stability

Methylisothiazolinone (MI) is one of the most used preservatives in shampoos and also one of the most effective. A preservative mixture known as Kathon™ CG is commercially available. It contains 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 2-methyl-4-isothiazolin-3-one (MI) (3:1) and stabilizers. The aim of this study is to evaluate the influence of formulation factors in the quantification and stability of isothiazolinones in shampoos. Two shampoo bases containing Kathon™ CG as a preservative were prepared. Some ingredients that are at risk of interfering with the preservative stability were added to these formulations. The preservative was quantified by HPLC-DAD (High-performance liquid chromatography with a diode-array detector) after preparation of the formulation and after storage at room temperature and at 40 °C. The addition of magnesium silicate proved to be essential for the breakdown of the interaction between the matrix and the analytes in the extraction procedure. The content of CMI/MI decreased right after preparation indicating that immediate interactions between CMI/MI and the ingredients may have occurred after preparation resulting in a decrease in the preservative concentration. Detrimental interactions between the ingredients, regarding the stability of the isothiazolinones were detected immediately after preparation and over time resulting in the reduction of CMI/MI concentration in these cosmetic shampoos.

scholarly journals The Effect of Tanreqing Injection on the Pharmacokinetics of Sirolimus in Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Zhang ◽  
Liang Sun ◽  
Jianxiu Zhai ◽  
Tianyi Xia ◽  
Wei Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Matrix Effects ◽  
Thaw Cycle ◽  
Relative Standard ◽  
The Matrix ◽  
Freeze Thaw Cycle ◽  
Liquid Chromatography Tandem Mass ◽  
The Stability ◽  
First Time

To evaluate the effect of Tanreqing injection on the pharmacokinetics of sirolimus in rats, a high performance liquid chromatography tandem mass spectrometry method was developed for sirolimus assay in whole blood. Calibration curve of sirolimus was acquired over a concentration ranging from 2.5 to 100 ng/mL with r2= 0.9955. The matrix effects and extraction recoveries of sirolimus ranged from 144% to 152% and from 80% to 96%, respectively. The inter- and intraday relative standard deviations were both <10%. The stability investigation showed that the blood samples were stable for 30-day-storage at -20°C, for 8 h storage at room temperature, for 24 h storage in the auto-sampler at 4°C, and for three freeze-thaw cycle process. The pharmacokinetic results demonstrated that the Cmax, AUC, and AUMC of sirolimus in rats (7.5 mg/kg, i.g.) were increased after beincoadministration with Tanreqing Injection at 2.5, 5.0, and 7.5 mL/kg (i.v.), respectively, or at 5 min, 2 h, and 4 h (5.0 mL/kg, i.v.) after SRL dosing, respectively. For the first time, the results proved the herb-drug interaction between Tanreqing Injection and sirolimus and accordingly suggested avoiding concurrent reception of those two drugs for patients.

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