scholarly journals In-situ STEM study on the morphological evolution of copper-based nanoparticles during high-temperature redox reactions

Nanoscale ◽  
2021 ◽  
Author(s):  
Sharmin Afroz Sharna ◽  
Mounib Bahri ◽  
Corinne Bouillet ◽  
Virgile Rouchon ◽  
Arnold Lambert ◽  
...  

Despite the broad relevance of copper nanoparticles in industrial applications, the fundamental understanding of oxidation and reduction of copper at the nanoscale is still a matter of debate and remains...

2014 ◽  
Vol 77 ◽  
pp. 00018 ◽  
Author(s):  
Mohamed Sadli ◽  
Frédéric Bourson ◽  
Ahmet Diril ◽  
Christophe Journeau ◽  
Dave Lowe ◽  
...  

1997 ◽  
Vol 482 ◽  
Author(s):  
T. B. Ng ◽  
J. Han ◽  
R. M. Biefeld ◽  
J. C. Zolper ◽  
M. H. Crawford ◽  
...  

AbstractIn-situ optical reflectance is used to monitor the morphological evolution of the two-step GaN growth on sapphire. The amount of H2 carrier gas used in the growth is observed to strongly influence the morphological evolution of the low temperature buffer layer and the subsequent high temperature nucleation behavior, which in turn affects the structural and electrical properties of the GaN epitaxial films. The optical reflectance transients correlate with the sizes and distributions of nuclei as observed by AFM.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ernesto Beltrán-Partida ◽  
Benjamín Valdez-Salas ◽  
Ernesto Valdez-Salas ◽  
Guillermo Pérez-Cortéz ◽  
Nicola Nedev

The design route, synthesis, and characterization of spherical copper nanoparticles with antifungal potential are reported in the present work. Copper nanoparticles were synthesized by a novel, inexpensive, and eco-friendly chemical reduction method using ascorbic acid as a reductant and stabilizer under reflux conditions. The characterization results showed the formation of homogeneous, dispersed, and stable spherical ascorbic acid-capped copper nanoparticles (CuNPs) with a diameter of 250 nm. The CuNPs exhibited sustained antifungal activity againstCandida albicans(C. albicans) after 24 h and even 48 h of incubation. Using enhanced dark-field microscopy, we presented the in situ interaction between CuNPs andC. albicans. Here, part of the interaction of CuNPs among theC. albicans, studied without the use of any chemical and/or physical fixing method, is discussed. The results indicate that part of the antifungal mechanism involves a promoted adhesion of CuNPs onto the cell wall and a massive accumulation of CuNPs into the fungal cells, concluding in cellular leakage. The cytotoxicity (viability) evaluations indicated that our CuNPs were more biocompatible after comparison to the Cu precursor and triclosan (a commercial antifungal drug). The synthesized CuNPs will open up a new road for their possible use as a potent antimicrobial agent for clinical and industrial applications.


Author(s):  
G.A. Botton ◽  
C.J. Humphreys

Transition metal aluminides are of great potential interest for high temperature structural applications. Although these materials exhibit good mechanical properties at high temperature, their use in industrial applications is often limited by their intrinsic room temperature brittleness. Whilst this particular yield behaviour is directly related to the defect structure, the properties of the defects (in particular the mobility of dislocations and the slip system on which these dislocations move) are ultimately determined by the electronic structure and bonding in these materials. The lack of ductility has been attributed, at least in part, to the mixed bonding character (metallic and covalent) as inferred from ab-initio calculations. In this work, we analyse energy loss spectra and discuss the features of the near edge structure in terms of the relevant electronic states in order to compare the predictions on bonding directly with spectroscopic experiments. In this process, we compare spectra of late transition metal (TM) to early TM aluminides (FeAl and TiAl) to assess whether differences in bonding can also be detected. This information is then discussed in terms of bonding changes at grain boundaries in NiAl.


Author(s):  
N. Rozhanski ◽  
A. Barg

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.


Alloy Digest ◽  
1974 ◽  
Vol 23 (2) ◽  

Abstract ALUMINUM 1100 is commercially pure aluminum and is characterized by its excellent ability to be drawn, spun, stamped or forged. It has good weldability, excellent resistance to corrosion and many home, architectural and industrial applications. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-44. Producer or source: Various aluminum companies. Originally published October 1956, revised February 1974.


Alloy Digest ◽  
1970 ◽  
Vol 19 (11) ◽  

Abstract PLATINUM is a soft, ductile, white metal which can be readily worked either hot or cold. It has a wide range of industrial applications because of its excellent corrosion and oxidation resistance and its high melting point. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Pt-1. Producer or source: Matthey Bishop Inc..


Alloy Digest ◽  
2007 ◽  
Vol 56 (10) ◽  

Abstract Kubota alloys HK40 and HK50 are austenitic Fe-Cr-Ni alloys that have been standard heat-resistant materials for more than four decades. With moderately high temperature strength, oxidation resistance, and carburization resistance the alloys are used in a wide variety of industrial applications. HK 50 has slightly higher carbon content. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on casting, heat treating, machining, and joining. Filing Code: SS-998. Producer or source: Kubota Metal Corporation, Fahramet Division.


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