scholarly journals Kinetics of the Lattice Response to Hydrogen Absorption in Thin Pd and CoPd Films

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3597
Author(s):  
Sudhansu Sekhar Das ◽  
Gregory Kopnov ◽  
Alexander Gerber
Keyword(s):  
Domain Wall ◽  
Crystal Lattice ◽  
Shape Memory ◽  
Hydrogen Absorption ◽  
Structural Response ◽  
Hydrogen Atmosphere ◽  
Type Model ◽  
Large Expansion ◽  
Kinetics Of ◽  
Plastic Creep

Hydrogen can penetrate reversibly a number of metals, occupy the interstitial sites and cause large expansion of the crystal lattice. The question discussed here is whether the kinetics of the structural response matches hydrogen absorption. We show that thin Pd and CoPd films exposed to a relatively rich hydrogen atmosphere (4% H2) inflate irreversibly, demonstrate the controllable shape memory, and duration of the process can be of orders of magnitude longer than hydrogen absorption. The dynamics of the out-of-equilibrium plastic creep are well described by the Avrami-type model of the nucleation and lateral domain wall expansion of the swelled sites.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Evaluating the high-pressure structural response and crystal lattice interactions of the magnetically-bistable organic radical TTTA

CrystEngComm ◽  
2021 ◽  
Author(s):  
Jonathan Richardson ◽  
Asato Mizuno ◽  
Yoshiaki Shuku ◽  
Kunio Awaga ◽  
Neil Robertson ◽  
...  
Keyword(s):  
High Pressure ◽  
Crystal Lattice ◽  
Structural Response ◽  
Pressure Response ◽  
Organic Radical ◽  
X Ray Diffraction ◽  
X Ray

Magnetic bistability has previously been observed and evaluated in an organic thiazyl radical 1,3,5 triathia 2,4,6-triazapentalenyl (TTTA). Herein, the structure-pressure response of TTTA has been evaluated by X-ray diffraction, where...

Kinetics of hydrogen absorption/desorption in TC21 alloy

2010 ◽  
Vol 490 (1-2) ◽  
pp. 562-567 ◽  
Author(s):  
Xiaoli Wang ◽  
Yongqing Zhao ◽  
Yaoqi Wang ◽  
Hongliang Hou ◽  
Weidong Zeng
Keyword(s):  
Hydrogen Absorption ◽  
Kinetics Of

Peierls “Washboard” Controls Dynamics of the Domain Walls in Molecular Ferrimagnets

2015 ◽  
Vol 233-234 ◽  
pp. 55-59
Author(s):  
Marina Kirman ◽  
Artem Talantsev ◽  
Roman Morgunov
Keyword(s):  
Domain Wall ◽  
Crystal Lattice ◽  
Domain Walls ◽  
Low Frequency ◽  
Domain Wall Motion ◽  
Lattice Parameter ◽  
Structural Defects ◽  
Crystal Lattice Parameter ◽  
Wall Width ◽  
Debye Relaxation

The magnetization dynamics of metal-organic crystals has been studied in low frequency AC magnetic field. Four modes of domain wall motion (Debye relaxation, creep, slide and over - barrier motion (switching)) were distinguished in [MnII(H(R/S)-pn)(H2O)] [MnIII(CN)6]⋅2H2O crystals. Debye relaxation and creep of the domain walls are sensitive to Peierls relief configuration controlled by crystal lattice chirality. Structural defects and periodical Peierls potential compete in the damping of the domain walls. Driving factor of this competition is ratio of the domain wall width to the crystal lattice parameter.

scholarly journals Comparing hydrogen absorption kinetics of the samples of intermetallic compound and metal hydride compact on its basis

2021 ◽  
Vol 2057 (1) ◽  
pp. 012043
Author(s):  
I A Romanov ◽  
V I Borzenko ◽  
A N Kazakov
Keyword(s):  
Intermetallic Compound ◽  
Metal Hydride ◽  
Hydrogen Absorption ◽  
Reaction Rate ◽  
Nickel Foam ◽  
High Confidence ◽  
Compact Sample ◽  
Kinetics Of ◽  
Rate Controlling Step ◽  
Absorption Of Hydrogen

Abstract This work is devoted to an experimental study and comparison of the kinetics of hydrogen absorption by an intermetallic compound LaNi4.4Al0.3Fe0.3 in form of pure intermetallic compound free backfill and a compact based on it obtained by cold pressing with a spiral matrix of nickel-foam. To calculate the kinetic parameters of the hydrogen absorption reaction, the initial rates method is used. The PCT absorption isotherms are measured at temperatures of 313, 333, and 353 K. The experimental data are described with quite high confidence by the chosen model, which assumes that the reaction rate controlling step is the dissociative absorption of hydrogen on the surface of the a-phase. The rate of hydrogen absorption increases with increasing pressure drop and temperature. It is shown that the rate of hydrogen absorption by the sample of pure IMC is significantly less dependent on temperature compared to the compact sample. In addition, the reaction rate at temperatures of 313 and 333 K is higher for the free backfill sample, and at 353 K it is higher for the metal hydride compact. The values of the absorption constant and the activation energy of the hydrogen absorption reaction are determined for both samples.

scholarly journals Study of the Complex Stiffness of a Vibratory Mechanical System with Shape Memory Alloy Coil Spring Actuator

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Samuell A. Holanda ◽  
Antonio A. Silva ◽  
Carlos J. de Araújo ◽  
Alberdan S. de Aquino
Keyword(s):  
Shape Memory ◽  
Mechanical System ◽  
Smart Materials ◽  
Excitation Frequency ◽  
Structural Response ◽  
Scientific Development ◽  
Temperature Control System ◽  
Coil Spring ◽  
Sensors And Actuators ◽  
Context Shape

The vibration control is an important area in the dynamic of structures that seeks to reduce the amplitude of structural responses in certain critical frequency ranges. Currently, the scientific development leads to the application of some actuators and sensors technologically superior comparing to the same features available on the market. For developing these advanced sensors and actuators, smart materials that can change their mechanical properties when subjected to certain thermomechanical loads can be employed. In this context, Shape memory alloys (SMAs) may be used for developing dynamic vibration dampers which are capable of acting on the system providing proper tuning of the excitation frequency and the natural frequency. This paper aims to analyze the behavior of the stiffness and damping of a SMA helical coil spring actuator coupled to a mechanical system of one degree of freedom (1 DOF) subjected to an unbalanced excitement force and a temperature control system. By analyzing the effect of these parameters on the structural response and considering the concept of complex stiffness, it can be possible to predict the system's behavior within certain acceptable ranges of vibration, already in the design phase.

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