Kinetics of Ni3Al cluster formation with decomposition of solid solution

2015 ◽  
Vol 10 (1-2) ◽  
pp. 85-88
Author(s):  
T. V. Kurikhina
Keyword(s):  
Solid Solution ◽  
Cluster Formation ◽  
Decomposition Of Solid Solution ◽  
Kinetics Of

scholarly journals Oxidation behavior of non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution powders in air

2021 ◽  
Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  
Keyword(s):  
Solid Solution ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Group Iv ◽  
Hypersonic Vehicles ◽  
Metal Carbides ◽  
Initial Oxidation ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Kinetics Of

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.

scholarly journals Kinetics of Insulin Aggregation: Disentanglement of Amyloid Fibrillation from Large-Size Cluster Formation

2006 ◽  
Vol 90 (12) ◽  
pp. 4585-4591 ◽  
Author(s):  
Mauro Manno ◽  
Emanuela Fabiola Craparo ◽  
Vincenzo Martorana ◽  
Donatella Bulone ◽  
Pier Luigi San Biagio
Keyword(s):  
Cluster Formation ◽  
Large Size ◽  
Amyloid Fibrillation ◽  
Kinetics Of

Decomposition of Solid Solution of the AA5083 Alloy upon Exposure to Elevated Temperatures

2000 ◽  
Vol 331-337 ◽  
pp. 1089-1094 ◽  
Author(s):  
D. Sampath ◽  
S. Moldenhauer ◽  
H.R. Schipper ◽  
K. Mechsner ◽  
A. Haszler
Keyword(s):  
Solid Solution ◽  
Elevated Temperatures ◽  
Decomposition Of Solid Solution ◽  
Aa5083 Alloy

Kinetic Assessment of the Dry Reforming of Methane over a Solid Solution Ni–La Oxide Catalyst

2021 ◽  
Author(s):  
Victor Stivenson Sandoval-Bohorquez ◽  
Edgar M. Morales-Valencia ◽  
Carlos Omar Castillo-Araiza ◽  
Luz Marina Ballesteros Rueda ◽  
Víctor Gabriel Baldovino Medrano
Keyword(s):  
Solid Solution ◽  
Active Sites ◽  
Oxide Catalyst ◽  
Bond Cleavage ◽  
Scale Up ◽  
Active Surface ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Nickel Surface ◽  
Kinetics Of

The dry reforming of methane is a promising technology for the abatement of CH<sub>4</sub> and CO<sub>2</sub>. Solid solution Ni–La oxide catalysts are characterized by their long–term stability (100h) when tested at full conversion. The kinetics of dry reforming over this type of catalysts has been studied using both power law and Langmuir–Hinshelwood based approaches. However, these studies typically deal with fitting the net CH<sub>4</sub> rate hence disregarding competing and parallel surface processes and the different possible configurations of the active surface. In this work, we synthesized a solid solution Ni–La oxide catalyst and tested six Langmuir–Hinshelwood mechanisms considering both single and dual active sites for assessing the kinetics of dry reforming and the competing reverse water gas shift reaction and investigated the performance of the derived kinetic models. In doing this, it was found that: (1) all the net rates were better fitted by a single–site model that considered that the first C–H bond cleavage in methane occurred over a <a>metal−oxygen </a>pair site; (2) this model predicted the existence of a nearly saturated nickel surface with chemisorbed oxygen adatoms derived from the dissociation of CO<sub>2</sub>; (3) the dissociation of CO<sub>2</sub> can either be an inhibitory or an irrelevant step, and it can also modify the apparent activation energy for CH<sub>4</sub> activation. These findings contribute to a better understanding of the dry reforming reaction's kinetics and provide a robust kinetic model for the design and scale–up of the process.

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