Activating Dinitrogen for Chemical Looping Ammonia Synthesis: Mn nitride layer growth modeling

AbstractThe synthesis of Al2O3-based functional materials having 10 vol. % of fine aluminum or titanium and aluminum-disperse or titanium-dispersed nitride hardened-particles has been explored. Two experimental steps have been set for the synthesis; specifically, sintering of Al2O3-aluminum or Al2O3-titanium powders which were thoroughly mixed under high energy ball-milling, pressureless-sintered at 1400°C during 1 h in argon atmosphere and then for the second step it was induced formation of aluminum nitride or titanium nitride at 500°C during different times (24, 72 and 120 h) by a nitriding process via immersion in ammoniac salts. SEM analyses of the microstructures obtained in nitride bodies were performed in order to know the effect of the ammoniac salts used as nitrating on the microstructure of aluminum or titanium for each studied functional material. It was observed that an aluminum nitride or titanium nitride layer growth from the surface into the bulk and reaches different depth as the nitriding time of the functional material was increased. The use of aluminum or titanium significantly enhanced density level and hardness of the functional materials.

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The Calculation of Kinetic Parameters in Manganese Nitriding

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.97-101.737 ◽

2010 ◽

Vol 97-101 ◽

pp. 737-742 ◽

Cited By ~ 1

Author(s):

Jin Zhu Zhang ◽

Shui Hui Luo ◽

Chu Shao Xu

Keyword(s):

Weight Gain ◽

Numerical Model ◽

Kinetic Parameters ◽

Growth Model ◽

Metallic Iron ◽

Nitride Layer ◽

Layer Growth ◽

Solid Metal ◽

Nitriding Temperature ◽

Set Up

The present work confirmed and achieved the relevant parameters which belong to the manganese nitriding model via experiments. Based on the metallic iron nitriding model and the nitride layer growth model, metal manganese nitrding model was set up. The change laws between the kinetic parameters and temperature of the solid metal manganese nitriding model was studied by using the optimum method. The experimental results showed that the ratio of weight gain for samples relatively increased with the increasing of nitriding temperature, and the results obtained from the numerical model indicated that the kinetic parameters of manganese nitriding model increased with the increasing of nitriding temperature.

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EB Surface Alloying and Plasma Nitriding of Different Al Alloys

Materials Science Forum ◽

10.4028/www.scientific.net/msf.690.91 ◽

2011 ◽

Vol 690 ◽

pp. 91-94 ◽

Cited By ~ 8

Author(s):

Anke Dalke ◽

Anja Buchwalder ◽

Heinz Joachim Spies ◽

Horst Biermann ◽

Rolf Zenker

Keyword(s):

Plasma Nitriding ◽

Load Capacity ◽

Matrix Material ◽

High Hardness ◽

Nitride Layer ◽

Layer Growth ◽

Research Field ◽

Al Alloys ◽

Wear Behaviour ◽

Surface Alloying

Within the last years, considerable progress was achieved in the research field of plasma nitriding of Al alloys. However, due to large property differences between the very hard AlN layer and the soft Al matrix material the load capacity of the nitride layer is limited. Electron beam (EB) surface alloying modifies the chemical composition of the area near the surface up to a certain depth. This, for instance, results in high hardness levels, and therefore this layer acts as support for the hard and wear-resistant thin AlN layer generated by plasma nitriding. In the present study, surface modifications produced by a combination of EB alloying with Fe based additives and plasma nitriding of wrought, cast and spray-formed Al alloys were investigated. After the EB treatment the layers were examined regarding their influence on the structure, the nitride layer growth mechanism, the effect of the EB layer for the support of the AlN layer and the resulting duplex layer properties, e.g. hardness and wear behaviour.

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Monitoring Nitride Layer Growth Using Magnetic Sensor

Surface Engineering ◽

10.1179/026708401101517791 ◽

2001 ◽

Vol 17 (3) ◽

pp. 193-200 ◽

Cited By ~ 8

Author(s):

J. Ratajski

Keyword(s):

Nitride Layer ◽

Layer Growth ◽

Magnetic Sensor

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Deposition of Copper Thin Films on Titanium Nitride Layer Prepared by Flow Modulation CVD Technology

Materials Science Forum ◽

10.4028/www.scientific.net/msf.449-452.457 ◽

2004 ◽

Vol 449-452 ◽

pp. 457-460

Author(s):

Nam Ihn Cho ◽

Min Chul Kim ◽

Kyung Hwa Rim ◽

Ho Jung Chang ◽

Keeyoung Jun ◽

...

Keyword(s):

Thin Films ◽

Titanium Nitride ◽

Diffusion Barrier ◽

High Vacuum ◽

Reduction Process ◽

Chemical Vapor ◽

Barrier Properties ◽

Nitride Layer ◽

Layer Growth ◽

Flow Modulation

Copper (Cu) thin films have been deposited onto titanium nitride (TiN) layer which was previously prepared by flow modulation chemical vapor deposition (FMCVD technology. The diffusion barrier properties of the TiN layer to Cu have been studied depending upon the post-annealing and the sample preparation conditions of the TiN layer. The Cu deposition has performed by RF magnetron sputtering with 5N target in the high vacuum ambient. The FMCVD process has carried out in a single CVD chamber by switching TiCl4flow to the argon flow cyclically, which creates sequential deposition of TiN layer and chlorine reduction process. The higher flow modulation cycle and Ar purge time during the TiN layer growth have been observed to provide the better diffusion barrier property in Auger depth profile and X-ray diffraction analysis.

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Ion beam synthesis of nitride layers in iron

Journal of Materials Research ◽

10.1557/jmr.1992.2689 ◽

1992 ◽

Vol 7 (10) ◽

pp. 2689-2712 ◽

Cited By ~ 31

Author(s):

A.M. Vredenberg ◽

C.M. Pérez-Martin ◽

J.S. Custer ◽

D.O. Boerma ◽

L. de Wit ◽

...

Keyword(s):

Ion Beam ◽

High Energy ◽

Nitride Layer ◽

Layer Growth ◽

Stable Phase ◽

Iron Nitride ◽

High Dose ◽

Nitride Layers ◽

Induced Defects ◽

Kinetics Of

Stoichiometric iron nitride layers have been synthesized by high dose, high energy nitrogen implantation into Fe using a two-step implantation process. First, a nitrogen preimplantation at ~100 °C is used to form nitride precipitates. A low temperature is necessary to restrict the nitrogen mobility. Second, 1 MeV implantation at ~300 °C leads to the formation of a stoichiometric γ′–Fe4N layer at the position of the preimplanted N atoms. Growth of this nitride layer proceeds by diffusion of the implanted N through either the α–Fe matrix (for 200 or 500 keV preimplantations) or the nitride layer itself (for 1 MeV preimplantation). During annealing above 350 °C the γ′ layers dissolve in a planar fashion, characterized by an activation energy of 2.3 eV. Phase formation during preimplantation and phase transformations during subsequent annealing or hot implantation can be understood from the thermodynamics for the Fe–N system, while the kinetics of layer growth is influenced by the beam-induced defects. The experiment and model suggest that γ′ is not a thermodynamically stable phase below 310 ± 10 °C and should decompose into α (ferrite) and ∊ nitride.

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