Particulate Intermetallic Matrix Composite Made by One-Step Pulsed Laser Deposition

1992 ◽  
Vol 273 ◽  
Author(s):  
Li-Chyong Chen ◽  
Ernest L. Hall ◽  
Karen A. Lou
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Optical Films ◽  
The Matrix ◽  
One Step ◽  
Intermetallic Matrix Composites

ABSTRACTA novel way of producing particulate intermetallic matrix composites based on Nb-Al in one step using pulsed laser deposition (PLD) has been investigated. One unique characteristic, inherent to laser ablation, is the generation of particulates. These particulates condense on the substrate and become part of the film. In some cases, such as in high Tc superconducting or optical films applications, it is believed that the presence of particulates diminishes the quality of the films. In this work, we demonstrate that it can be advantageous in some applications to incorporate these particulates into the films.Nb-Al films were prepared by laser ablation from a Nb3Al target using a 248nm KrF excimer laser at various fluences and substrate temperatures. Transmission (TEM) and scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and Auger electron spectroscopy (AES) were used to characterize the samples. The resultant films consist of a homogeneous matrix with uniformly distributed inclusions. The size of the particles generated by PLD is in the range of a few tens of nanometers to a few microns. EDX shows that the matrix has a composition of Nb7A13 and the particulates contain barely detectable Al. The mechanism of the depletion of Al in the particulates will be discussed. The merit of having a ductile Nb phase embedded in the intermetallic matrix is evident as the cracks generated during TEM sample thinning process propagate in the brittle matrix and finally are arrested at the ductile inclusions.

scholarly journals Rapid Synthesis of Metallic Reinforced in Situ Intermetallic Composites in Ti-Al-Nb System via Resistive Sintering

2018 ◽  
Vol 16 (1) ◽  
pp. 869-875
Author(s):  
Mediha İpek ◽  
Tuba Yener ◽  
Gözde Ç. Efe ◽  
Ibrahim Altınsoy ◽  
Cuma Bindal ◽  
...  
Keyword(s):  
High Hardness ◽  
Processing Technique ◽  
Metallic Phase ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
One Step ◽  
Intermetallic Matrix Composites ◽  
Hardness Values ◽  
A Current

AbstractIntermetallics are known as a group of materials that draws attention with their features such as ordered structure, high temperature resistance, high hardness and low density. In this paper, it is aimed to obtain intermetallic matrix composites and also to maintain some ductile Nb and Ti metallic phase by using 99.5% purity, 35-44 μm particle size titanium, niobium and aluminium powders in one step via recently developed powder metallurgy processing technique - Electric current activated/assisted sintering system (ECAS). In this way, metallic reinforced intermetallic matrix composites were produced. Dominant phases of TiAl3 and NbAl3 which were the first compounds formed between peritectic reaction of solid titanium, niobium and molten aluminum in Ti-Al-Nb system during 10, 30 and 90 s for 2000 A current and 1.5-2.0 voltage were detected by XRD and SEM-EDS analysis. Hardness values of the test samples were measured by Vickers indentation technique and it was detected that the hardnesses of intermetallic phases as 411 HVN whereas ductile metallic phase as 120 HVN.

scholarly journals Electroanalytical Performance of Nitrogen-Doped Graphene Films Processed in One Step by Pulsed Laser Deposition Directly Coupled with Thermal Annealing

Materials ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 666 ◽  
Author(s):  
Florent Bourquard ◽  
Yannick Bleu ◽  
Anne-Sophie Loir ◽  
Borja Caja-Munoz ◽  
José Avila ◽  
...  
Keyword(s):  
High Temperature ◽  
Pulsed Laser Deposition ◽  
Graphene Film ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Synthesis Process ◽  
Nitrogen Doped ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
One Step

Graphene-based materials are widely studied to enable significant improvements in electroanalytical devices requiring new generations of robust, sensitive and low-cost electrodes. In this paper, we present a direct one-step route to synthetize a functional nitrogen-doped graphene film onto a Ni-covered silicon electrode substrate heated at high temperature, by pulsed laser deposition of carbon in the presence of a surrounding nitrogen atmosphere, with no post-deposition transfer of the film. With the ferrocene methanol system, the functionalized electrode exhibits excellent reversibility, close to the theoretical value of 59 mV, and very high sensitivity to hydrogen peroxide oxidation. Our electroanalytical results were correlated with the composition and nanoarchitecture of the N-doped graphene film containing 1.75 at % of nitrogen and identified as a few-layer defected and textured graphene film containing a balanced mixture of graphitic-N and pyrrolic-N chemical functions. The absence of nitrogen dopant in the graphene film considerably degraded some electroanalytical performances. Heat treatment extended beyond the high temperature graphene synthesis did not significantly improve any of the performances. This work contributes to a better understanding of the electrochemical mechanisms of doped graphene-based electrodes obtained by a direct and controlled synthesis process.

Ultrafast Pulsed Laser Deposition of Chalcogenide Glass Films for Low-loss Optical Waveguides

2003 ◽  
Vol 780 ◽  
Author(s):  
B. Luther-Davies ◽  
V. Z. Kolev ◽  
M. J. Lederer ◽  
R. Yinlan ◽  
M. Samoc ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Repetition Rate ◽  
Pulsed Laser ◽  
Fused Silica ◽  
Laser Deposition ◽  
Process Conditions ◽  
High Optical Quality ◽  
Optical Films ◽  
Wide Range ◽  
Deposited Films

AbstractUltra-fast pulsed laser deposition using high-repetition-rate short-pulse lasers has been shown to provide high optical quality, super smooth thin films free of scattering centres. The optimized process conditions require short ps or sub-ps pulses with repetition rate in the range 1-100 MHz, depending on the target material. Ultra-fast pulsed laser deposition was used to successfully deposit atomically-smooth, 5micron thick As2S3 films. The as-deposited films were photosensitive at wavelengths close to the band edge (≈520 nm) and waveguides could be directly patterned into them by photo-darkening using an Argon ion or frequency doubled Nd:YAG laser. The linear and nonlinear optical properties of the films were measured as well as the photosensitivity of the material. The optical losses in photo-darkened waveguides were <0.2 dB/cm at wavelengths beyond 1200nm and <0.1 dB/cm in as-deposited films. The third order nonlinearity, n2,As2S3, was measured using both four-wave mixing and the z-scan technique and varied with wavelength from 100 to 200 times fused silica (n2,Silica ≈3×10-16 cm2/W) between 1500nm and 1100nm with low nonlinear absorption.Encouraged by the Ultrafast laser deposition results, we have built a new specialized modelocked picosecond laser system for deposition of optical films and for laser formation of nanoclusters. The newly developed “state of the art” powerful Nd:YVO laser can operate over a wide range of wavelengths, intensities, and repetition rates in MHz range. A brief description of the 50W laser installation is presented.

scholarly journals One-step preparation of N-doped strontium titanate films by pulsed laser deposition

2007 ◽  
Vol 89 (4) ◽  
pp. 933-940 ◽  
Author(s):  
I. Marozau ◽  
M. Döbeli ◽  
T. Lippert ◽  
D. Logvinovich ◽  
M. Mallepell ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Strontium Titanate ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
One Step

Laser ablation mass spectrometry: a tool to investigate matter transfer processes during pulsed-laser deposition experiments

2002 ◽  
Vol 186 (1-4) ◽  
pp. 282-287 ◽  
Author(s):  
Frédéric Aubriet ◽  
Nouari Chaoui ◽  
Rachel Chety ◽  
Benoı̂t Maunit ◽  
Eric Millon ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Transfer Processes ◽  
Matter Transfer

Quantum Confinement of GaAs Nanocrystals Deposited on PMMA Microspheres Using Pulsed Laser Ablation

2013 ◽  
Vol 660 ◽  
pp. 3-9
Author(s):  
Jeong Ho Ryu ◽  
Soon Yong Kweon ◽  
Jung Il Lee ◽  
Sung Lim Ryu
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Quantum Confinement ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Average Diameter ◽  
Laser Deposition ◽  
Spherical Particles ◽  
Novel Approach

A modified pulsed laser deposition (PLD) was employed to deposit GaAs nanocrystals on the surface of PMMA microspheres. This novel approach is distinguished by the fact that laser ablated materials are deposited uniformly onto the surface of spherical particles that are held constantly in a particle fludization unit. The XRD, SEM, EDX, TEM, EDP and PL results confirmed that cubic structured GaAs nanocrystals were deposited uniformly on the surface of PMMA microspheres with an average diameter of about 15 nm.

THE TARGET MORPHOLOGY DURING PULSED LASER DEPOSITION OF HYDROXYAPATITE THIN FILMS

2005 ◽  
Vol 12 (04) ◽  
pp. 539-543 ◽  
Author(s):  
QUANHE BAO ◽  
CHUANZHONG CHEN ◽  
LUBIN CHEN ◽  
DIANGANG WANG ◽  
TINGQUAN LEI ◽  
...  
Keyword(s):  
Thin Films ◽  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
The Other ◽  
Laser Deposition ◽  
Grain Structure ◽  
Before And After ◽  
Modified Surface ◽  
Modified Surface Layer

A modified surface layer of hydroxyapatite (HA) target was observed before and after pulsed laser deposition. Two types of HA targets were used for laser ablation. We observed that the surface morphology of the target has a very fine compacted grain structure and presents many irregularities with some microroughness and microporosity before laser ablation. The laser ablated regions can be divided into two areas: one area is porous and rough but the other is dense and smooth. The percentage of particles in the films was high for the films produced with targets that were sintered at 1200°C.

scholarly journals Substrate Temperature-Dependent Structural, Optical, and Electrical Properties of Thermochromic VO2(M) Nanostructured Films Grown by a One-Step Pulsed Laser Deposition Process on Smooth Quartz Substrates

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ali Hendaoui
Keyword(s):  
Substrate Temperature ◽  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Laser Deposition ◽  
Processing Temperature ◽  
Present Contribution ◽  
Valence States ◽  
One Step ◽  
Quartz Substrates

Thermochromic M-phase vanadium dioxide VO2(M) films with different morphologies have been grown directly on smooth fused quartz substrates using low deposition rate pulsed laser deposition without posttreatment. When the substrate temperature was increased in the range 450°C–750°C, better (011) texturization of VO2(M) films was observed along with an enhancement of their crystallinity. Morphology evolved from small-grained and densely packed VO2(M) grains at 450°C to less packed micro/nanowires at 750°C. Mechanisms behind the crystallinity/morphology evolution were discussed and correlated with the effect of the temperature on the diffusion of the adatoms as well as on the V5+ valence states content in VO2(M) films. Resistivity measurements as a function of temperature revealed that the insulator-to-metal transition features of VO2(M) films (i.e., transition temperature (TIMT), resistivity variation (ΔR), hysteresis width (ΔH), and transition sharpness (ΔT)) are strongly dependent on the processing temperature. In terms of optical properties, it was found that the open (i.e., porous) structure of the films achieved at high temperature induced an improvement of their luminous transmittance. Simultaneously, the enhancement of the films crystallinity with the temperature resulted in better IR modulation ability. The present contribution provides a one-step process to control the morphology of VO2(M) films grown on smooth quartz substrates for applications as switches, memory devices, and smart windows.

scholarly journals Dynamics of Transient Plasmas Generated by ns Laser Ablation of Memory Shape Alloys

2020 ◽  
Author(s):  
Stefan Andrei Irimiciuc ◽  
Norina Forna ◽  
Andrei Agop ◽  
Maricel Agop ◽  
Stefan Toma ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Pulsed Laser Deposition ◽  
Emission Spectroscopy ◽  
Pulsed Laser ◽  
Optical Emission ◽  
Laser Deposition ◽  
Global Dynamics ◽  
Time Resolved ◽  
Laser Ablation Process ◽  
Key Techniques

Understanding the underline fundamental mechanism behind experimental and industrial technologies embodies one of the foundations of the advances and tailoring new materials. With the pulsed laser deposition being one of the key techniques for obtaining complex biocompatible materials with controllable stoichiometry, there is need for experimental and theoretical advancements towards understanding the dynamics of multi component plasmas. Here we investigate the laser ablation process on Cu-Mn-Al and Fe-Mn-Si by means of space-and time-resolved optical emission spectroscopy and fast camera imaging. In a fractal paradigm the space–time homographic transformations were correlated with the global dynamics of the ablation plasmas.

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