Pulsed Laser And Ion Beam Surface Modification of Sintered, Alpha-Sic

1985 ◽  
Vol 51 ◽  
Author(s):  
K. L. More ◽  
R. F. Davis ◽  
B. R. Appleton ◽  
D. Lowndes ◽  
P. Smith
Keyword(s):  
Electron Microscopy ◽  
Surface Modification ◽  
Laser Annealing ◽  
Ion Beam ◽  
Pulsed Laser ◽  
High Energy ◽  
Strength Increase ◽  
Ion Beam Mixing ◽  
Krf Excimer Laser ◽  
Surface Modification Techniques

ABSTRACTPulsed laser annealing and ion beam mixing have been used as surface modification techniques to enhance the physical properties of polycrystalline α-SiC. Thin Ni overlayers (20 nm - 100 nm) were evaporated onto the SiC surface. The specimens were subsequently irradiated with pulses of a ruby or krypton fluoride (KrF) excimer laser or bombarded with high energy Xe+ or Si+ ions. Both processes are non-equilibrium methods and each has been shown to induce unique microstructural changes at the SiC surface which are not attainable by conventional thermal treatments. Under particular (and optimum) processing conditions, these changes considerably increased the mechanical properties of the SiC; following laser irradiation, the fracture strength of the SiC was increased by as much as 50%, but after ion beam mixing, no strength increase was observed.High resolution cross-section transmission electron microscopy (X-TEM), scanning electron microscopy (SEM), and Rutherford backscattering techniques were used to characterize the extent of mixing between the Ni and the SiC as a result of the surface modification.

An investigation of ion beam and pulsed laser Ni-SiC mixed surface structures by cross-sectional TEM

1986 ◽  
Vol 44 ◽  
pp. 512-513
Author(s):  
K. L. More
Keyword(s):  
Surface Modification ◽  
Fracture Strength ◽  
Laser Annealing ◽  
Ion Beam ◽  
Pulsed Laser ◽  
High Energy ◽  
Strength Increase ◽  
Cross Sectional ◽  
Krf Excimer Laser ◽  
Surface Modification Techniques

Ion beam and pulsed laser mixing have been used as surface modification techniques in an attempt to increase the mechanical properties of sintered α-SiC. Thin Ni overlayers (50 nm - 100 nm) were evaporated onto the SiC surface and subsequently irradiated with pulses of a krypton-fluoride (KrF) excimer laser or bombarded with high energy Si+ ions. Both techniques are non-equilibrium processing methods capable of inducing unique microstructural changes at the specimen surface which, under particular processing conditions, can result in enhanced physical properties. It has been shown previously that laser annealing of Ni-coated α-SiC resulted in a fracture strength increase of ≈20%; however, the fracture strength was not changed following ion beam mixing. High resolution cross-sectional transmission electron microscopy (X-TEM) was used to characterize the extent of mixing between the Ni and the SiC following surface modification.

High-energy (MeV) ion-beam mixing of Ti with SiC and Si3N4

1987 ◽  
Vol 2 (2) ◽  
pp. 211-215 ◽  
Author(s):  
R. S. Bhattacharya ◽  
A. K. Rai ◽  
P. P. Pronko
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Cross Section ◽  
Ion Beam ◽  
Enthalpy Of Mixing ◽  
High Energy ◽  
Rutherford Backscattering ◽  
Ion Beam Mixing ◽  
Metal Insulator ◽  
Transmission Electron

Ion-beam mixing of Ti layers with sintered α-SiC and hot-pressed Si3N4 was measured for 1 McV Au+ at doses of 1X1016 cm−2 and 5X1016 cm−2. Rutherford backscattering (RBS) and cross-section transmission electron microscopy (XTEM) were used to evaluate the mixing. Mixing was observed in Ti/SiC system; however, there was no mixing in Ti/Si3N4 system. Results are discussed in light of the enthalpy of mixing criterion for metal-insulator systems.

scholarly journals Plasma Immersion Surface Modification With Metal Ion Plasma

1991 ◽  
Vol 223 ◽  
Author(s):  
I. G. ◽  
X. Godechot ◽  
K. M. Yu
Keyword(s):  
Surface Modification ◽  
Ion Implantation ◽  
Metal Ion ◽  
Plasma Deposition ◽  
Ion Beam ◽  
High Energy ◽  
Ion Beam Mixing ◽  
Metal Plasma ◽  
Modified Surface ◽  
Plasma Guns

ABSTRACTWe describe here a novel technique for surface modification in which a metal plasma is employed and by which various blends of plasma deposition and ion implantation can be obtained. The new technique is a variation of the plasma immersion technique described by Conrad and co-workers. When a substrate is immersed in a metal plasma, the plasma that condenses on the substrate remains there as a film, and when the substrate is then implanted, qualitatively different processes can follow, including ‘conventional’ high energy ion implantation, recoil implantation, ion beam mixing, ion beam assisted deposition, and metallic thin film and multilayer fabrication with or without species mixing. Multiple metal plasma guns can be used with different metal ion species, films can be bonded to the substrate through ion beam mixing at the interface, and multilayer structures can be tailored with graded or abrupt interfaces. We have fabricated several different kinds of modified surface layers in this way.

Ion Beam Mixing of Ni-Ti Bilayered Thin Films

1985 ◽  
Vol 43 ◽  
pp. 290-291
Author(s):  
A. K. Rai ◽  
R. S. Bhattacharya ◽  
M. H. Rashid
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Amorphous Alloys ◽  
Ion Beam ◽  
Ion Bombardment ◽  
High Energy ◽  
Mixing Efficiency ◽  
Ion Beam Mixing ◽  
Enhanced Diffusion ◽  
Binary Metal

Ion beam mixing has recently been found to be an effective method of producing amorphous alloys in the binary metal systems where the two original constituent metals are of different crystal structure. The mechanism of ion beam mixing are not well understood yet. Several mechanisms have been proposed to account for the observed mixing phenomena. The first mechanism is enhanced diffusion due to defects created by the incoming ions. Second is the cascade mixing mechanism for which the kinematicel collisional models exist in the literature. Third mechanism is thermal spikes. In the present work we have studied the mixing efficiency and ion beam induced amorphisation of Ni-Ti system under high energy ion bombardment and the results are compared with collisional models. We have employed plan and x-sectional veiw TEM and RBS techniques in the present work.

Pulsed Laser Annealing of Aluminum

1980 ◽  
Vol 1 ◽  
Author(s):  
W. R. Wampler ◽  
D. M. Follstaedt ◽  
P. S. Peercy
Keyword(s):  
Single Crystal ◽  
Laser Irradiation ◽  
Reasonable Agreement ◽  
Ruby Laser ◽  
Laser Annealing ◽  
Ion Beam ◽  
Pulsed Laser ◽  
Nucleation Time ◽  
Pulsed Laser Annealing ◽  
Beam Analysis

ABSTRACTPulsed ruby laser irradiation of unimplanted single crystal and implanted polycrystalline Al has been studied with ion beam analysis and TEM. The results show that Al is melted to a depth of ∼ 0.9 μm with a 4.2 J/cm2 , 15 nsec pulse, and that vacancies are quenched into Al during resolidification. Diffusion of Zn in liquid Al is observed, and a melt time of ∼ 65 nsec is estimated for a 3.8 J/cm2, 30 nsec pulse. The observations are in reasonable agreement with calculations of sample temperature and melt times. We observe no precipitation of AlSb in liquid Al for Sbimplanted Al, and conclude that the nucleation time satisfies 50 nsec ≲ tnuc ≲ 200 nsec. We find no evidence for amorphous Al after irradiation of single crystal Al with energies ≳ 1.5 J/cm2.

Fabrication of Ni–Al thin films by the pulsed laser deposition technique

1992 ◽  
Vol 7 (10) ◽  
pp. 2639-2642 ◽  
Author(s):  
R.K. Singh ◽  
Deepika Bhattacharya ◽  
S. Sharan ◽  
P. Tiwari ◽  
J. Narayan
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Rutherford Backscattering Spectrometry ◽  
Pulsed Laser ◽  
High Energy ◽  
Laser Deposition ◽  
Nanosecond Laser ◽  
X Ray ◽  
Target Composition

We have fabricated Ni3Al and NiAl thin films on different substrates by the pulsed laser deposition (PLD) technique. A high energy nanosecond laser beam was directed onto Ni–Al (NiAl, Ni3Al) targets, and the evaporated material was deposited onto substrates placed parallel to the target. The substrate temperature was varied between 300 and 400 °C, and the substrate-target distance was maintained at approximately 5 cm. The films were analyzed using scanning electron microscopy, transmission electron microscopy, x-ray diffraction, and Rutherford backscattering spectrometry. At energy densities slightly above the evaporation threshold, a slight enrichment of Al was observed, while at higher energy densities the film stoichiometry was close (<5%) to the target composition. Barring a few particles, the surface of the films exhibited a smooth morphology. X-ray and TEM results corroborated the formation of Ni3Al and NiAl films from similar target compositions. These films were characterized by small randomly oriented grains with grain size varying between 200 and 400 Å.

scholarly journals Ion-Beam Mixing and Tribology of Fe/B Multilayers

1989 ◽  
Vol 157 ◽  
Author(s):  
Renyuan Hu ◽  
L. E. Rehn ◽  
G. R. Fenske ◽  
P. M. Baldo
Keyword(s):  
Electron Microscopy ◽  
Irradiation Dose ◽  
Activation Enthalpy ◽  
Ion Beam ◽  
Rutherford Backscattering ◽  
Arrhenius Behavior ◽  
Ion Beam Mixing ◽  
Steel Substrates ◽  
M50 Steel

ABSTRACTInterdiffusion of Fe and B trilayer specimens during 1-MeV Kr+ bombardment was studied using Rutherford backscattering and electron microscopy. The square of the interdiffusion distance during mixing at 300°C was found to depend linearly on the irradiation dose. Arrhenius behavior with an apparent activation enthalpy of 0.7 eV was observed for the mixing between 200 and 500°C. Electron microscopy of ion-beam mixed multilayer specimens revealed that two crystalline compounds, Fe2B and Fe3B, formed during bombardment at 450°C, while two different amorphous Fe/B phases formed at 300°C. Substantially improved adhesion and reduced friction were observed for Fe/B multilayers ion-beam mixed onto M50 steel substrates at 450°C.

Preferential Crystallization of β-FeSi2 from Micro-droplets Generated by Laser Ablation.

2004 ◽  
Vol 848 ◽  
Author(s):  
Aiko Narazaki ◽  
Tadatake Sato ◽  
Yoshizo Kawaguchi ◽  
Hiroyuki Niino
Keyword(s):  
Laser Ablation ◽  
Room Temperature ◽  
Crystallization Behavior ◽  
Laser Annealing ◽  
Pulsed Laser ◽  
Excimer Laser Ablation ◽  
Pulsed Laser Annealing ◽  
Molten Droplets ◽  
Equilibrium Process ◽  
Krf Excimer Laser

ABSTRACTβ-FeSi2 was successfully fabricated at room temperature via the deposition of molten micro-droplets generated by the KrF excimer laser ablation. Only the molten droplets precipitated as the β-FeSi2 crystalline phase on a silicon substrate kept even at room temperature, whereas the rest of film was amorphous. The crystallization behavior of micro-droplets has been discussed in the light of non-equilibrium process due to rapid cooling on the substrate. After the deposition, pulsed laser annealing was also performed in order to improve the crystallinity of the β-FeSi2 microprecipitates-containing film.

Surface Modification by Ion Beam Enhanced Deposition

1983 ◽  
Vol 27 ◽  
Author(s):  
R. A. Kant ◽  
B. D. Sartwell
Keyword(s):  
Electron Microscopy ◽  
Surface Modification ◽  
Ion Beam ◽  
Auger Spectroscopy ◽  
Copper Films ◽  
Lateral Migration ◽  
Multiple Sequences

ABSTRACTCopper films given multiple sequences of Ta implantation and Cu depositions were analyzed using electron microscopy, backscattering, and Auger spectroscopy. Ta retention is 92% following direct implantation, and 100% retention was achieved for the same Ta dose if sputtered Cu is replaced during implantation. Lateral migration of Ta and microroughness were observed for all cases studied. Evidence for TaC formation is presented.

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