Solid state amorphization reactions in deformed Ni-Zr multilayered composites

1990 ◽  
Vol 5 (3) ◽  
pp. 488-497 ◽  
Author(s):  
G. C. Wong ◽  
W. L. Johnson ◽  
E. J. Cotts
Keyword(s):  
Thermal Stability ◽  
Solid State ◽  
Amorphous Phase ◽  
Equilibrium Phase ◽  
Solid State Reactions ◽  
Heat Of Mixing ◽  
Scanning Calorimetry ◽  
Multilayered Composites ◽  
State Amorphization ◽  
Thermal Stability Of

The mechanisms of metallic glass formation and competing crystallization processes in mechanically-deformed Ni-Zr multilayered composites have been investigated by means of differential scanning calorimetry and x-ray diffraction. Our investigation of the heat of formation of amorphous NixZr1−x alloys shows a large negative heat of mixing (on the order of 30 kJ/mole) for compositions near Zr55Ni45 with a compositional dependence qualitatively similar to that predicted by mean field theory. We find that the products of solid state reactions in composites of Ni and Zr can be better understood in terms of the equilibrium phase diagram and the thermal stability of liquid quenched metallic glasses. We have determined the composition of the growing amorphous phase at the Zr interface in these Ni-Zr diffusion couples to be 55 ± 4% Zr. We investigated the kinetics of solid state reactions competing with the solid state amorphization reaction and found the value of the activation energy of the initial crystallization and growth of the growing amorphous phase to be 2.0 ± 0.1 eV, establishing an upper limit on the thermal stability of the growing amorphous phase.

Kinetics and Thermal Stability of Ni/Zr Multilayer Thin-Film Diffusion Couple during a Solid State Amorphization Reaction

1986 ◽  
Vol 77 ◽  
Author(s):  
W. J. Meng ◽  
E. J. Cotts ◽  
W. L. Johnson ◽  
W. M. Keck
Keyword(s):  
Thermal Stability ◽  
Solid State ◽  
Enthalpy Of Mixing ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thin Film Diffusion ◽  
Kinetics Of ◽  
State Amorphization ◽  
Thermal Stability Of ◽  
Amorphous Phase Formation

ABSTRACTDifferential scanning calorimetry and X-ray diffraction have been utilized to monitor the solid state amorphization reaction in crystalline Ni/Zr multilayers. Enthalpy of mixing of amorphous NiZr alloys has been measured. Kinetics of amorphous phase formation and thermal stability have been discussed in some detail.

Solid State Reactions in Mechanically Deformed Composites in the Ni-Zr and the Ni-Ti Systems

1989 ◽  
Vol 170 ◽  
Author(s):  
B. E. White ◽  
M. E. Patt ◽  
E. J. Cotts
Keyword(s):  
Solid State ◽  
Amorphous Material ◽  
Nucleation And Growth ◽  
Solid State Reactions ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Disordered Phase ◽  
Multilayered Composites ◽  
High Degree

AbstractDifferential scanning calorimetry and x-ray diffraction analysis were utilized to monitor solid state reactions in mechanically deformed Ni/Ti multilayered composites. Solid state reactions at temperatures less than = 650 K result in the formation of a highly disordered phase which is apparently amorphous.The subsequent nucleation and growth at higher temperatures of intermetallic compounds from the amorphous phase is examined. The relatively small thickness of amorphous material (less than 100 Å) which can be grown by solid state reaction in our Ni/Ti samples, combined with the indication that a disordered interface such as that produced by mechanical deformation facilitates these reactions in the Ni-Ti system, may provide some explanation for the relatively high degree of success experienced in the production of amorphous Ni- Ti by means of ball milling. Comparisons are made to results obtained in the Ni-Zr system.

Crystallization Behavior and Thermal Stability of Two-Glassy Phase ZR-Based Bulk Metallic Glasses

2010 ◽  
Vol 89-91 ◽  
pp. 562-567
Author(s):  
P.H. Tsai ◽  
I.S. Huang ◽  
T.H. Li ◽  
Jason S.C. Jang ◽  
J.C. Huang ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Amorphous Alloy ◽  
Crystallization Behavior ◽  
Heat Of Mixing ◽  
Interface Area ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Thermal Stabilities ◽  
Activation Energy Of Crystallization ◽  
Thermal Stability Of

Based on the thermodynamic calculation, two phase separated Zr-based BMGs (Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10) which developed by the authors previous study were selected for investigating their crystallization behavior and thermal stabilities by means of differential scanning calorimetry (DSC), and X-ray diffractometry. The results show that the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits higher GFA than the Zr63.8Ni16.2Cu15Al5 amorphous alloy. But the Zr63.8Ni16.2Cu15Al5 amorphous alloy presents higher activation energy of crystallization (227 kJ/mole and 188 kJ/mole for Zr63.8Ni16.2Cu15Al5 and Zr66Cu15.3Ni8.7Al10 BMGs, respectively). However, Zr66Cu15.3Ni8.7Al10 amorphous alloy contains less atomic percentage of Cu and Ni elements (with positive heat of mixing) may result in forming less volume phase separation as well less interface area between these separated amorphous phase. Overall, the Zr66Cu15.3Ni8.7Al10 amorphous alloy exhibits longer incubation time at higher annealing temperature in comparison with the Zr63.8Ni16.2Cu15Al5 amorphous alloy, suggesting that the amorphous alloy which contains fewer amounts of Cu and Ni elements would have better thermal stability.

Amorphous-phase formation and initial reactions at Pt/GaAs interfaces

1991 ◽  
Vol 49 ◽  
pp. 858-859
Author(s):  
Dae-Hong Ko ◽  
Robert Sinclair
Keyword(s):  
Solid State ◽  
Amorphous Phase ◽  
Phase Formation ◽  
Compound Semiconductor ◽  
Metal Compound ◽  
Heat Of Mixing ◽  
Semiconductor Interface ◽  
Direct Demonstration ◽  
State Amorphization ◽  
Amorphous Phase Formation

It is now well known that many metals form a l-2nm amorphous interdiffused layer when deposited onto clean Si surface, which grows upon annealing in some systems but crystallizes into stable, or metastable, phases in others. Such behavior can be interpreted in terms of a solid-state amorphization, driven by a negative heat of mixing of the elements with the amorphous phase produced for kinetic reasons. Some metal/compound semiconductor systems also show the same reaction behavior. Though there have been some reports, using electron diffraction, on the amorphous phase formation at metal-compound semiconductor interface upon low temperature annealing, because the expected thickness might only be several atomic layers, it is clear that high resolution transmission electron microscopy (HRTEM) is the most powerful technique to study such a phase. This article reports on the amorphous phase formation and the initial stages of reaction occuring at Pt/GaAs interfaces upon annealing with HRTEM, and this is the most direct demonstration of solid state amorphization of a metal with a compound semiconductor.

Solid-State Reactions of SiC/W-25Re Alloy and Thermal Stability of SiC/Ti/W-25Re Alloy under High-Temperature Annealing

2016 ◽  
Vol 18 (9) ◽  
pp. 1574-1580
Author(s):  
Jun Sae Han ◽  
Seung Sik Jang ◽  
Dong Yong Park ◽  
Yong Jun Oh ◽  
Seong Jin Park
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Solid State ◽  
Solid State Reactions ◽  
High Temperature Annealing ◽  
Thermal Stability Of

Solid state reactions between Pd and Si induced by high energy ball milling

1994 ◽  
Vol 9 (1) ◽  
pp. 53-60 ◽  
Author(s):  
D.L. Zhang ◽  
T.B. Massalski
Keyword(s):  
Solid State ◽  
Ball Milling ◽  
Amorphous Phase ◽  
Metastable Phase ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Solid State Reactions ◽  
Scanning Calorimetry ◽  
Energy Ball ◽  
Si Content

Solid state reactions induced by high energy ball milling between Pd and Si have been studied. X-ray diffractometry and differential scanning calorimetry have been used to characterize the resulting phases. During milling, Pd and Si react by diffusion to form different phases depending on the Si content in the starting mixture. With a low Si content of 19 at. %, an amorphous phase forms of the same composition. On continued milling, this amorphous phase partially crystallizes into Pd9Si2 and Pd2Si compounds. With the Si content equal to or higher than 33 at. %, no amorphous phases were observed. Instead, the Pd2Si phase is produced. For powder composition corresponding to the stoichiometric compound Pd2Si (33 at. % Si), the Pd2Si forms and remains stable during further milling. With Si content equal to or higher than 50 at. %, the initially produced Pd2Si is destabilized by a reaction with the remaining Si to form PdSi, which is a metastable phase at the temperature of ball milling. It is very unlikely that an amorphous phase of a composition equal to or higher than 33 at. % Si could be produced by ball milling in the Pd-Si system. This is because the Pd2Si phase forms very easily through the reaction between Pd and Si, and this reaction competes effectively with glass formation.

Thermal Stability of N-Heterocycle-Stabilized Iodanes – A Systematic Investigation

2019 ◽  
Author(s):  
Andreas Boelke ◽  
Yulia A. Vlasenko ◽  
Mekhman S. Yusubov ◽  
Boris Nachtsheim ◽  
Pavel Postnikov
Keyword(s):  
Thermal Stability ◽  
Differential Scanning Calorimetry ◽  
Thermogravimetric Analysis ◽  
Systematic Investigation ◽  
Scanning Calorimetry ◽  
Thermal Stability Of

<p>The thermal stability of pseudocyclic and cyclic <i>N</i>-heterocycle-stabilized (hydroxy)aryl- and mesityl(aryl)-l<sup>3</sup>-iodanes (NHIs) through thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is investigated. NHIs bearing <i>N</i>-heterocycles with a high N/C-ratio such as triazoles show among the lowest descomposition temperatures and the highest decomposition energies. A comparison of NHIs with known (pseudo)cyclic benziodoxolones is made and we further correlated their thermal stability with reactivity in a model oxygenation. </p>

scholarly journals Isothermal Vulcanization and Non-Isothermal Degradation Kinetics of XNBR/Epoxy/XNBR-g-Halloysite Nanotubes (HNT) Nanocomposites

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2872
Author(s):  
Seyed Mohamad Reza Paran ◽  
Ghasem Naderi ◽  
Elnaz Movahedifar ◽  
Maryam Jouyandeh ◽  
Krzysztof Formela ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Halloysite Nanotubes ◽  
Butadiene Rubber ◽  
Order Model ◽  
Scanning Calorimetry ◽  
Theoretical Methods ◽  
Vulcanization Kinetics ◽  
Kinetics Of ◽  
Thermal Stability Of

The effect of several concentrations of carboxylated nitrile butadiene rubber (XNBR) functionalized halloysite nanotubes (XHNTs) on the vulcanization and degradation kinetics of XNBR/epoxy compounds were evaluated using experimental and theoretical methods. The isothermal vulcanization kinetics were studied at various temperatures by rheometry and differential scanning calorimetry (DSC). The results obtained indicated that the nth order model could not accurately predict the curing performance. However, the autocatalytic approach can be used to estimate the vulcanization reaction mechanism of XNBR/epoxy/XHNTs nanocomposites. The kinetic parameters related to the degradation of XNBR/epoxy/XHNTs nanocomposites were also assessed using thermogravimetric analysis (TGA). TGA measurements suggested that the grafted nanotubes strongly enhanced the thermal stability of the nanocomposite.

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