Effect of Pack Al Content on Growth Kinetics at 650 °C of Ni2Al3 Coating Layer on Nickel-Electroplated Creep Resistant Ferritic Steels

2011 ◽  
Vol 399-401 ◽  
pp. 2008-2012
Author(s):  
D.J. Wu ◽  
W.H. Hua ◽  
Z.D. Xiang ◽  
C.Y. Zhu
Keyword(s):  
Layer Thickness ◽  
Growth Kinetics ◽  
Coating Layer ◽  
Ferritic Steels ◽  
Minimum Level ◽  
Powder Mixtures ◽  
Al Content ◽  
Nickel Electroplating ◽  
Kinetics Of ◽  
Pack Cementation Process

The hybrid Ni2Al3/Ni coating was formed on creep resistant ferritic steels by firstly nickel electroplating and then partially aluminising the Ni layer at 650 °C by pack cementation process using powder mixtures of Al, AlCl3and Al2O3. The effect of pack Al content (W) on growth kinetics of the outer Ni2Al3layer of the coating was investigated by varying it from 2 to 10 wt% whilst keeping the pack AlCl3content constant at 2 wt% and aluminising conditions at 650°C/4h. It was revealed that, once W was above a minimum level, the growth of the outer Ni2Al3layer thickness depended linearly on W1/2. The possible reasons for such growth kinetics were discussed.

scholarly journals Microstructures and Oxidation Behaviors of Silicide Coated Nb Alloys by Halide Activated Pack Cementation Process

2020 ◽  
Vol 58 (8) ◽  
pp. 507-514
Author(s):  
Wonchul Yang ◽  
Choong-Heui Chung ◽  
Sangyeob Lee ◽  
Kyeong Ho Baek ◽  
Youngmoo Kim ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Coating Layer ◽  
Pack Cementation ◽  
Powder Mixtures ◽  
Arc Melting ◽  
Static Oxidation ◽  
Coating Layers ◽  
Pack Cementation Process ◽  
Coating Layer Thickness ◽  
Oxidation Behaviors

In this study, we tried to improve the oxidation resistance of Nb-12Si (wt%) alloys at 1200 °C or higher through pack cementation coatings. Nb-12Si (wt%) alloys were prepared by arc-melting under Ar atmosphere. When the alloys were coated using pack powder mixtures composed of Si, Al2O3 and NaF, two silicide layers composed of NbSi2 and Nb5Si3 phases were successfully produced on the substrate. The Si-pack coatings were performed with various heat treatment temperatures and time conditions. The microstructures and thickness changes of the coating layers were analyzed to determine the growth behaviors of the coating layer. The growth constant of 8.4 10–9 cm2/sec was obtained with a diffusion growth mode. In addition, in order to examine the resistance of the Si-pack coated alloys, isothermal static oxidation tests were performed at 1200 °C and higher temperatures. As a result, the oxidation resistance of the alloys was determined by protecting the surface of the alloys with silicide oxide layers formed by the silicide coatings. The uncoated specimens exhibited an abnormal weight increase due to the formation of Nb oxide. The coated specimen showed excellent oxidation resistance at 1200 °C for up to 12 hrs, while the previous reports on the same alloy verified oxidation resistance only up to 1100 °C. It appears that the excellent oxidation resistance is closely related to the NbSi2 coating layer thickness. The oxidation behaviors of the coating layers after the oxidation tests were discussed in terms of microstructural and phase analyses.

Influence of Al on scale formation and growth kinetics of 10wt.% Cr creep resistant ferritic steels at 650°C in air

2014 ◽  
Vol 80 ◽  
pp. 374-382 ◽  
Author(s):  
S. Tang ◽  
S. Zhu ◽  
X. Tang ◽  
H. Pan ◽  
X. Chen ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Scale Formation ◽  
Ferritic Steels ◽  
Kinetics Of

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

Growth kinetics of boride layers formed on GGG 40.3 ductile iron

2016 ◽  
Vol 58 (5) ◽  
pp. 418-421
Author(s):  
Fatma Ünal ◽  
Ahmet Topuz
Keyword(s):  
Growth Kinetics ◽  
Ductile Iron ◽  
Kinetics Of

scholarly journals Study of deposition parameters and growth kinetics of ZnO deposited by aerosol assisted chemical vapor deposition

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18493-18499
Author(s):  
Sergio Sánchez-Martín ◽  
S. M. Olaizola ◽  
E. Castaño ◽  
E. Urionabarrenetxea ◽  
G. G. Mandayo ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Growth Kinetics ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Kinetics Analysis ◽  
Deposition Parameters ◽  
Kinetics Of

Impact of deposition parameters, microstructure and growth kinetics analysis of ZnO grown by Aerosol-assisted Chemical Vapor Deposition (AACVD).

scholarly journals Morphology, energetics and growth kinetics of diphenylalanine fibres

2021 ◽  
Author(s):  
Phillip Mark Rodger ◽  
Caroline Montgomery ◽  
Giovanni Costantini ◽  
Alison Rodger
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Growth Kinetics ◽  
Dynamics Simulations ◽  
Kinetics Of

The formation and stability of diphenylalanine fibres are studied by combining molecular dynamics simulations with microscopy and spectroscopy experiments, quantitatively detailing their morphology, energetics and growth kinetics.

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