scholarly journals The Effects of Modifying the Activity of Nitriding Media by Diluting Ammonia with Nitrogen

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2432
Author(s):  
Mihai Ovidiu Cojocaru ◽  
Mihai Branzei ◽  
Andrei Mihai Ghinea ◽  
Leontin Nicolae Druga
Keyword(s):  
Growth Kinetics ◽  
Nitrided Layer ◽  
Gaseous Mixture ◽  
Ammonia Nitrogen ◽  
Layer Growth ◽  
Gaseous Ammonia ◽  
Kinetics Parameters ◽  
Nitrogen Dilution ◽  
Nitrogen Mixture ◽  
Kinetics Of

This paper discusses the issue of the effects of modifying the activity of nitriding media by diluting ammonia with nitrogen and the concomitant variation in the degree of ammonia dissociation on the layer’s growth kinetics and their phase composition. To understand and quantify the effects of the variation in the main parameters that influence the layer growth kinetics, the experimental programming method was used and mathematical models of interactions between influence and kinetics parameters were obtained for two metallic materials: Fe-ARMCO and 34CrAlMo5 nitralloy steel. It was concluded that the nitriding operating temperature and the degree of nitrogen dilution of the ammonia have statistically significant influences on the kinetics of the nitrided layer. In the same context, it was analytically proved and experimentally confirmed that the ammonia degree dissociation from the gaseous ammonia-nitrogen mixture, along with the dilution degree of the medium with nitrogen, significantly influences the nitrogen potential of the gaseous mixture used for nitriding and thus the concentration of nitrogen in balance at the medium thermochemically processed metal product interface.

Characterization and growth kinetics of plasma nitrided layer fabricated on Incoloy 901 superalloy

2020 ◽  
Vol 396 ◽  
pp. 125960
Author(s):  
Hongjian Huang ◽  
Xiaowei Wei ◽  
Haiyan He ◽  
Yuhao Wu ◽  
Jianhui Qiu
Keyword(s):  
Growth Kinetics ◽  
Nitrided Layer ◽  
Kinetics Of

Growth kinetics of MgB2 layer and interfacial MgO layer during ex situ annealing of amorphous boron film

2004 ◽  
Vol 19 (10) ◽  
pp. 3081-3089 ◽  
Author(s):  
Hyun-Mi Kim ◽  
Sung-Soo Yim ◽  
Ki-Bum Kim ◽  
Seung-Hyun Moon ◽  
Young-Woon Kim ◽  
...  
Keyword(s):  
Growth Kinetics ◽  
Interfacial Layer ◽  
Surface Reaction ◽  
Layer Growth ◽  
Ex Situ ◽  
Amorphous Boron ◽  
Cross Sectional ◽  
Transmission Electron ◽  
Kinetics Of ◽  
Rough Surface Morphology

This paper describes the growth kinetics of an interfacial MgO layer as well as those of an MgB2 layer during ex situ annealing of the evaporated amorphous boron (a-B) film under Mg vapor overpressure. A thin MgO layer is formed at the interface between a-B and Al2O3 substrate before the formation of crystalline MgB2 layer and the interfacial layer is epitaxially related with Al2O3 substrate (MgO (111)[110] // Al2O3 (0001)[1100]). The interfacial MgO layer continues to grow during the annealing, and its apparent growth rate is about 0.1 nm/min. The analysis of MgB2 layer growth kinetics using cross-sectional transmission electron microscopy reveals that there exist two distinct growth fronts at both sides of an MgB2 layer. The growth kinetics of the lower MgB2 layer obeys the parabolic rate law during the entire annealing time. The growth of the upper MgB2 layer is controlled by the surface reaction between out-diffused boron and Mg vapor up to 10 min, resulting in a rough surface morphology of MgB2 layer. By considering the mass balance of Mg and boron during ex situ annealing, we obtained the diffusivities of Mg and boron in MgB2 layer which were in the same order range of approximately 10−12 cm2/s.

The Kinetics of Gas Nitrided Layer Growth on Austenitic Stainless Steel

2010 ◽  
Vol 297-301 ◽  
pp. 573-578 ◽  
Author(s):  
Jolanta Baranowska
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Nitrided Layer ◽  
Light And Electron Microscopy ◽  
Layer Growth ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treated Steel ◽  
Optical Spectrometry ◽  
Kinetics Of

This paper presents the results of investigations on gas nitrided austenitic stainless steel. The treatment was conducted at various temperatures (400-515°C), gas compositions of atmospheres used (20-100% NH3) and times (0.5-12h). The layers were investigated by X-ray diffraction, Light and Electron Microscopy and Glow Discharge Optical Spectrometry. The kinetics of layer growth has been analysed in terms of the process parameters and compared with the data presented for plasma treated steel. The specific nitrogen profiles of nitrided layers are discussed in the context of the layers’ microstructure and phase composition.

Growth Kinetics of Hardened Layers Produced during Nitriding in Ammonia Gas Environments

2006 ◽  
Vol 526 ◽  
pp. 109-114 ◽  
Author(s):  
S. Mridha
Keyword(s):  
Growth Kinetics ◽  
White Layer ◽  
Nitrided Layer ◽  
Case Depth ◽  
Iron Nitride ◽  
Gas Mixture ◽  
Optimum Level ◽  
Low Alloy Steels ◽  
Ammonia Content ◽  
Kinetics Of

In gas nitriding the thickness of the case depth is reported to increase parabolically with processing time and ammonia content in the NH3/H2 gas mixture which consequently increases the thickness of undesirable surface iron-nitride (white layer). In this investigation two commercial grade low alloy steels were nitrided in gas atmospheres containing 10 to 80% ammonia at 4700, 5200 and 5700C for 6 to 96 h. A metallographic technique was used to reveal different zones of the nitrided surface and the thickness of the diffusion zone was recorded using microscope. The growth kinetics of the diffusion layer of these two steels were analyzed and compared with that of 3% chromium (En40B) steel from literature. The results of the investigation conclusively suggest that the growth rate of the nitrided layer for both steels reached to a maximum with the increase of ammonia content in the gas mixture up to an optimum level where the thickness of the white layer is a minimum. However, the growth rates of the nitrided case are different for different steels.

GROWTH KINETICS OF Cu(Al) SOLID SOLUTION IN Al/Cu DIFFUSION COUPLES

2004 ◽  
Vol 11 (03) ◽  
pp. 337-340 ◽  
Author(s):  
E. B. HANNECH ◽  
N. LAMOUDI ◽  
A. GASMI
Keyword(s):  
Solid Solution ◽  
Growth Kinetics ◽  
Early Stage ◽  
Pure Aluminum ◽  
Layer Growth ◽  
Solid Solution Phase ◽  
Diffusion Couples ◽  
Phase Layer ◽  
Initial Stage ◽  
Kinetics Of

The growth kinetics of the solid solution phase of aluminum in copper in diffusion couples of pure aluminum and copper has been investigated at 425°C using a scanning electron microscope. In the initial stage, the phase layer growth was found to obey the parabolic law, indicating that the rate-controlling process is diffusion. At longer times, the growth rate deviates from the kt-1/2 behavior of the early stage.

Growth Kinetics of Intermetallic Compound and Interfacial Reactions in Pb-Free Flip Chip Solder Bump during Solid State Isothermal Aging

2005 ◽  
Vol 486-487 ◽  
pp. 273-276
Author(s):  
Dae Gon Kim ◽  
Hyung Sun Jang ◽  
Young Jig Kim ◽  
Seung Boo Jung
Keyword(s):  
Solid State ◽  
Intermetallic Compound ◽  
Growth Kinetics ◽  
Isothermal Aging ◽  
Flip Chip ◽  
Compound Layer ◽  
Layer Growth ◽  
Intermetallic Compound Layer ◽  
Temperature Range ◽  
Kinetics Of

In the present work, the growth kinetics of intermetallic compound layer formed in Sn-3.5Ag flip chip solder joints by solid-state isothermal aging was examined at temperatures between 80 and 150 °C for 0 to 60 days. The bumping for the flip chip devices was performed using an electroless under bump metallization. The quantitative analyses were performed on the intermetallic compound layer thickness as a function of aging time and aging temperature. The layer growth of the Ni3Sn4 intermetallic compound followed a parabolic law within a given temperature range. As a whole, because the value of the time exponent (n) is approximately equal to 0.5, the layer growth of the intermetallic compound was mainly controlled by diffusion mechanism in the temperature range studied. The apparent activation energy of the Ni3Sn4 intermetallic was 49.63 kJ/mol.

Diffusional Growth Kinetics of Boride Layers on Iron-Chromium Alloys

2008 ◽  
Vol 138 ◽  
pp. 181-188 ◽  
Author(s):  
Vasil I. Dybkov ◽  
L.V. Goncharuk ◽  
V.G. Khoruzha ◽  
K.A. Meleshevich ◽  
A.V. Samelyuk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Growth Kinetics ◽  
Reaction Times ◽  
Layer Growth ◽  
Diffusional Growth ◽  
Chromium Alloys ◽  
Layer Growth Rate ◽  
Linear Differential ◽  
Kinetics Of ◽  
Iron Chromium

Two boride layers were found to form at the interface of iiron-chromiium alllloys (10 and 25% Cr) or an industrial 13% Cr steel and boron at 850-950 oC and reaction times in the range 1-12 h. In the case of a Fe-10% Cr alloy and the steel, the layers are based on the FeB and Fe2B compounds. With a Fe-25% Cr alloy, the constituent phases are FeB and CrB for the outer layer and Fe2B and Cr2B for the inner layer. Both layers are characterized by a pronounced texture. Diffusional growth kinetics of boride layers are close to parabolic and can alternatively be described by a system of two non-linear differential equations, producing a good fit to the experimental data. The temperature dependence of the layer growth-rate constants obeys a relation of the Arrhenius type.

Growth Kinetics of Intermetallic Compounds at the Interface of Liquid Sn-9Zn/Cu

2011 ◽  
Vol 233-235 ◽  
pp. 2323-2327
Author(s):  
Hui Zhen Huang ◽  
Xiu Qin Wei ◽  
Lang Zhou
Keyword(s):  
Activation Energy ◽  
Intermetallic Compound ◽  
Intermetallic Compounds ◽  
Solder Alloy ◽  
Growth Kinetics ◽  
Layer Growth ◽  
Experimental Results ◽  
Cu Substrate ◽  
Diffusion Mechanisms ◽  
Kinetics Of

The morphology and growth of the intermetallic compound (IMC) formed between liquid Sn-9Zn eutectic solder alloy and Cu at 220-260°C was investigated. Experimental results showed that γ-Cu5Zn8 was present at the Sn-9Zn/Cu interface as the reaction product. The IMC layer growth follows the parabolic-growth law, which indicates that the growth of the IMC is controlled by the diffusion mechanisms. The activation energy of γ-Cu5Zn8 layer growth for liquid Sn-9Zn reacting with Cu substrate is determined as 50.5 KJ/mol.

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