Synthesis of Crystallized TiNi Films by Ion Irradiation

2012 ◽  
Vol 78 ◽  
pp. 87-91
Author(s):  
Noriaki Ikenaga ◽  
Yoichi Kishi ◽  
Zenjiro Yajima ◽  
Noriyuki Sakudo
Keyword(s):  
Shape Memory ◽  
Crystallization Temperature ◽  
Ion Irradiation ◽  
Deposition Process ◽  
Plasma Potential ◽  
Micro Electro Mechanical Systems ◽  
Ion Energy ◽  
Crystal Film ◽  
Irradiation Energy ◽  
New Apparatus

TiNi is well known as a typical shape-memory alloy, and is expected to be a promising material for micro actuators. In order to realize micro electro mechanical systems (MEMS) with this material, we have to get thin crystal film of the material, since the shape-memory property appears only when the structure is crystalline. In our previous studies we developed a new apparatus as well as a new deposition process for lowering the crystallization temperature by using ion irradiation. In addition, we have found that the deposited film by the process can be crystallized at very low temperature (below 473 K) without annealing but with simultaneous irradiation of Ar ions during sputter-deposition. In this study, we aim for the realization of crystallized TiNi film, which is deposited on Si substrate below 373 K substrate temperature. In order to realization the purpose, we have revealed the effect of Ar ion energy on lowering the crystallization temperature. The ion energy is measured with a quadrupole mass spectrometer (QMS) having an ion energy analyzer. The deposited TiNi films are examined with an X-ray diffraction (XRD). We found the plasma potential against the reactor chamber is important to be considered in the ion irradiation energy. The effects of ion energy for the crystallization of TiNi film are discussed.

Effect of Ion Irradiation on α and β Phase Evolution of Sputtered Tantalum Thin Films

2006 ◽  
Vol 979 ◽  
Author(s):  
Marek Sosnowski
Keyword(s):  
Thin Films ◽  
Ion Irradiation ◽  
Phase Evolution ◽  
Film Structure ◽  
Crystallographic Structure ◽  
Zero Bias ◽  
Ion Energy ◽  
Α Phase ◽  
Deposition Parameters ◽  
Irradiation Energy

AbstractTantalum thin films were deposited by RF (13.56 MHz) magnetron sputtering on silicon and aluminum substrates with ion irradiation (~ 0.3 mA per sqaure cm) controlled by applying different DC bias voltages (0-300 V) to the substrate. The presence of two main crystallographic phases of Ta in deposited films was investigated. Results showed that only the tetragonal â-phase formed in thin Ta films on both Si <100> and Al substrates at zero bias voltage (ion energy ~10 eV), and only bcc α-phase of Ta formed at the ion irradiation energy to 150 eV. Both phases were present at the ion energy of 100 eV. With increase of the ion energy to 250 eV, or higher, â-phase Ta dominated the film structure on Si <100> but not on Al substrate. Ta films were deposited in compressive stress with the lowest stress measured for α-phase Ta films deposited with ion energy of 150 eV. A new set of deposition parameters, significantly different than those previously reported, for low temperature growth Ta films with bcc crystallographic structure, desired for most applications, was found. An advantage of the new deposition parameters is relatively simplicity of the required equipment, which can be easily scaled up for an industrial process.

scholarly journals Comparative Study of Two Nanoindentation Approaches for Assessing Mechanical Properties of Ion-Irradiated Stainless Steel 316

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 719 ◽  
Author(s):  
Michael Saleh ◽  
Zain Zaidi ◽  
Christopher Hurt ◽  
Mihail Ionescu ◽  
Paul Munroe ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Section ◽  
Ion Irradiation ◽  
Thin Layers ◽  
Experimental Conditions ◽  
Irradiation Energy ◽  
Depth Analysis ◽  
Deformation Processes ◽  
Stainless Steel 316 ◽  
Hardness Values

Nanoindentation is a commonly used method to measure the hardness of surfaces with thin layers, and is especially useful in studying the change in mechanical properties of ion irradiated materials. This research compares two different methods of nanoindentation to study the changes in hardness resulting from ion irradiation of SS316 alloy. The samples were irradiated by He2+ ions at beam energies of 1, 2, and 3 MeV, respectively. The first method involves the indentation of the irradiated surface perpendicular to it using the continuous stiffness mode (CSM), while the second applies the indents on an oblique surface, accessing an inclined cross-section of the irradiated material. Finite element modelling has been used to further illuminate the deformation processes below the indents in the two methods. The hardness profiles obtained from the two nanoindentation methods reveal the differences in the outcomes and advantages of the respective procedures, and provide a useful guideline for their applicability to various experimental conditions. It is shown through an in depth analysis of the results that the ‘top-down’ method is preferable in the case when the ion irradiation energy, or, equivalently, the irradiated depth is small, due to its greater spatial resolution. However, the oblique cross section method is more suitable when the ion irradiation energy is >1 MeV, since it allows a more faithful measurement of hardness as a function of dose, as the plastic field is much smaller and more sensitive to local hardness values.

The effects of ion irradiation on NiTi shape memory alloy thin films

1999 ◽  
Vol 342 (1-2) ◽  
pp. 67-73 ◽  
Author(s):  
Florent Goldberg ◽  
Émile J. Knystautas
Keyword(s):  
Thin Films ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Ion Irradiation ◽  
Niti Shape Memory Alloy

Fabrication of an Apatite/Collagen Composite Coating on the NiTi Shape Memory Alloy through Electrochemical Deposition and Coating Characterisation

2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Composite Coating ◽  
Electrochemical Deposition ◽  
Room Temperature ◽  
Composite Coatings ◽  
Deposition Process ◽  
Niti Shape Memory Alloy ◽  
X Ray ◽  
Niti Sma

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.

Size Scale Dependence of Deformation in NiTi

2000 ◽  
Author(s):  
Ken Gall ◽  
Martin L. Dunn ◽  
Yiping Liu ◽  
Paul Labossiere ◽  
Huseyin Sehitoglu ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Shape Memory ◽  
Quantitative Information ◽  
Scale Dependence ◽  
Micro Electro Mechanical Systems ◽  
Testing Techniques ◽  
Shape Memory Materials ◽  
Mems Testing ◽  
Micro Indentation

Abstract Recent work [1-5] has suggested that a lucrative future for shape memory materials such as NiTi is in the area of micro-electro-mechanical systems (MEMS). To design MEMS and predict their behavior during service, we must have quantitative information on the mechanical properties of scaled down NiTi materials. One way of obtaining the mechanical properties of scaled down materials is with unique MEMS testing fixtures. Although this approach is favorably analogous to macroscopic testing techniques it is not always feasible owing to the difficulty of handling the microscopic samples. Many smart material actuators are deposited thin films [1-5] and separating the films from their substrate and subsequently testing them is beyond our current MEMS processing and handling tools. An alternative method to quantify the properties of microscale materials is through micro-indentation, which has been previously applied to NiTi polycrystals [6]. Although micro-indentation is simple to accomplish, interpretation and quantification of the results is not as straightforward, as will be demonstrated in this work.

Suppression of Martensitic Phase Transformation, Shape Memory and High Damping by Ion Implantation in Ni-Ti Thin Films

2006 ◽  
Vol 319 ◽  
pp. 17-24
Author(s):  
Rolf Gotthardt
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Memory Effect ◽  
Ion Irradiation ◽  
Amorphous State ◽  
Amorphous Layer ◽  
Martensitic Phase ◽  
Martensitic Phase Transformation ◽  
Damping Capacity

The shape memory effect and the high damping in shape memory alloys are based on the martensitic phase transformation, which takes place essentially without diffusion and any change of order have an influence on its side effects: the memory effect, the superelasticity and the high damping capacity of the martensitic phase. A new method to control the performance of shape memory alloys is presented, which is based on selective modification of specified parts of working components. In this research, ion irradiation has been used to introduce locally disorder into a crystal or even amorphise it. A pre-deformed Ni-Ti, 6μm thin film in its martensitic state has been irradiated with Ni-ions of energy of 5 MeV up to a dose of 1016 ions/cm2. By this treatment, a 2μm thin surface layer has been finally transformed into an amorphous state, in which the martensitic transformation is suppressed. During heating the underlying non-modified layer is contracting and an out-of-plane movement is observed. The amorphous layer is elastically deformed and its energy is used during cooling to bring the film in its original shape. In this way, a reversible movement of the film is created. This new technique not only allows us to design new types of micro-actuators, but also to influence locally the high damping, which can be of great importance for micro-engineering applications.

Energetic ion irradiation induced crystallization of Ni–Mn–Sn ferromagnetic shape memory alloy thin film

Vacuum ◽  
2013 ◽  
Vol 89 ◽  
pp. 190-196 ◽  
Author(s):  
R. Vishnoi ◽  
R. Singhal ◽  
K. Asokan ◽  
J.C. Pivin ◽  
D. Kanjilal ◽  
...  
Keyword(s):  
Thin Film ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Ion Irradiation ◽  
Alloy Thin Film ◽  
Ferromagnetic Shape Memory Alloy ◽  
Ferromagnetic Shape Memory ◽  
Induced Crystallization

Time-Resolved X-Ray Scattering Study of Co Surface Evolution during Low-Energy Ion Irradiation

2000 ◽  
Vol 647 ◽  
Author(s):  
O. Malis ◽  
J. M. Pomeroy ◽  
R. L. Headrick ◽  
J. D. Brock
Keyword(s):  
Ion Irradiation ◽  
Local Order ◽  
Layer By Layer ◽  
Surface Evolution ◽  
Time Resolved ◽  
Ion Energy ◽  
X Ray ◽  
X Ray Scattering ◽  
Characteristic Wavelength ◽  
Ray Scattering

AbstractThe sputter-erosion of hcp Co (0001) single crystal with Ar+ ions in the 100 to 700 eV energy range was investigated using in-situ time-resolved x-ray scattering. At temperatures above 300°C the surface remains relatively smooth, erosion evolving through a layer-by-layer or step flow mechanism. In this regime the ions have a smoothening effect on the surface and the resulting roughness decreases with increasing ion energy. Below 300°C the surface develops a pattern of mounds or pits with a characteristic wavelength. The time, ion energy and temperature dependence of this wavelength were studied in detail. Epitaxial Co thin films thermally evaporated on sapphire were also sputtered through in order to synthesize self-assembled arrays of Co nanoclusters with a narrow size distribution. The degree of local order within the Co dot arrays was examined using atomic force microscopy.

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