scholarly journals Control of kinetics of plasma assisted nitriding process of Ni-base alloys by substrate roughness

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Surface Preparation ◽  
Substrate Roughness ◽  
Grit Blasting ◽  
Process Kinetics ◽  
Responsible Mechanism ◽  
Complex Chemistry ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractThe present study investigated the effect of surface roughness on plasma assisted nitriding (PAN) process kinetics of Ni-base alloys. Two model alloys, namely Ni-10Cr and Ni-14Cr-4Al (wt.%) and commercial Rene 80, were examined. To elucidate the effect of surface roughness on nitriding kinetics, three methods of surface preparation were used, (1) polishing up with 1 μm diamond suspension, (2) grinding up to 220 grit sand-paper, and (3)grit blasting. The samples from each type of material were nitrided under the same conditions and investigated after processing. It was found that increase in roughness results in decreasing nitriding kinetics. The decrease of nitriding kinetics depends on alloy chemical composition, namely more complex chemistry resulted in smaller decrease of kinetics. Moreover, grit-blasting was found to be an improper method for surface preparation for PAN. The responsible mechanism for the effect of surface roughness on PAN kinetics of Ni-base alloys was proposed.

scholarly journals Effect of Surface Roughness on Oxidation Resistance of Stainless Steel AISI 316Ti During Exposure at High Temperature

2020 ◽  
Vol 29 (12) ◽  
pp. 8060-8069
Author(s):  
Wojciech J. Nowak
Keyword(s):  
Surface Roughness ◽  
Stainless Steel ◽  
Oxidation Resistance ◽  
Surface Preparation ◽  
Surface Region ◽  
Lower Surface ◽  
Near Surface ◽  
Steel Aisi ◽  
Kinetics Of ◽  
Effect Of Surface

AbstractIn the present work, the influence of surface roughness on oxidation kinetics of AISI 316Ti stainless steel and its consequences in term of oxidation resistance were investigated. Namely, the effect of surface roughness on oxidation resistance was evaluated during different types of cyclic oxidation tests at 900 and 1000 °C. The obtained results revealed that alloy possessing higher surface roughness showed longer lifetime compared to that with lower surface roughness. It was also found that more severe cyclic conditions suppressed the positive effect of surface roughness on sample’s lifetime. The better oxidation resistance of rougher alloy was correlated with suppressed formation of Fe-rich nodules on ground surfaces and explained by the combined effect of introduced defects in the near-surface region and possible increase in residual stresses caused by mechanical surface preparation.

scholarly journals Effect of Substrate Roughness on Oxidation Resistance of an Aluminized Ni-Base Superalloy

Metals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 782 ◽  
Author(s):  
Wojciech J. Nowak ◽  
Kamil Ochał ◽  
Patrycja Wierzba ◽  
Kamil Gancarczyk ◽  
Bartek Wierzba
Keyword(s):  
Oxidation Resistance ◽  
Diffusion Processes ◽  
Preparation Method ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Chemical Vapor ◽  
Substrate Roughness ◽  
Grit Blasting ◽  
Alumina Particles ◽  
Base Superalloy

In the present work, it is shown that the surface preparation method used on two Ni-based superalloys prior to aluminizing chemical vapor deposition (CVD) is one of the most important factors determining the oxidation resistance of aluminized Ni-based superalloys. It was found that grit-blasting the substrate surface negatively affects the oxidation resistance of the aluminized coatings. For grit-blasted and aluminized IN 625, a thicker outer NiAl coating was formed compared to that of IN 738. In contrast, no effect on NiAl coating thickness was found for grit-blasted and aluminized IN 738. However, a thicker interdiffusion zone (IDZ) was observed. It was shown that the systems with grit-blasted surfaces reveal worse oxidation resistance during thermal shock tests—namely, a higher mass loss was observed for both grit-blasted and aluminized alloys, as compared to ground and aluminized alloys. A possible reason for this effect of remaining alumina particles originating from surface grit-blasting on the diffusion processes and stress distribution at the coating/substrate is proposed.

Effect of surface roughness on the kinetics of mass transfer during gas carburizing*

2008 ◽  
Vol 63 (5) ◽  
pp. 257-264 ◽  
Author(s):  
O. Karabelchtchikova ◽  
Chr. A. Brown ◽  
R. D. Sisson
Keyword(s):  
Mass Transfer ◽  
Surface Roughness ◽  
Gas Carburizing ◽  
Kinetics Of ◽  
Effect Of Surface

scholarly journals Effect of surface roughness, chemical composition, and native oxide crystallinity on the orientation of self-assembled GaN nanowires on Ti foils

2017 ◽  
Vol 28 (42) ◽  
pp. 425602 ◽  
Author(s):  
G Calabrese ◽  
S V Pettersen ◽  
C Pfüller ◽  
M Ramsteiner ◽  
J K Grepstad ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Native Oxide ◽  
Gan Nanowires ◽  
Self Assembled ◽  
Effect Of Surface

Effect of surface roughness and chemical composition on the wetting properties of silicon-based substrates

2013 ◽  
Vol 16 (1) ◽  
pp. 65-72 ◽  
Author(s):  
Yannick Coffinier ◽  
Gaëlle Piret ◽  
Manash R. Das ◽  
Rabah Boukherroub
Keyword(s):  
Surface Roughness ◽  
Chemical Composition ◽  
Wetting Properties ◽  
Silicon Based ◽  
Effect Of Surface

scholarly journals Effect of Surface Roughness on Early Stage Oxidation Behavior of Ni-Base Superalloy IN 625

2018 ◽  
Vol 1 (3) ◽  
pp. 32 ◽  
Author(s):  
Wojciech Nowak
Keyword(s):  
Surface Roughness ◽  
Oxidation Behavior ◽  
Early Stage ◽  
Surface Preparation ◽  
Horizontal Tube ◽  
Optical Emission ◽  
Emission Spectrometry ◽  
Ground Sample ◽  
Base Superalloy ◽  
Effect Of Surface

In the present work the effect of surface roughness on oxidation behavior during the early stages of high temperature exposure of Ni-base superalloy IN 625 is described. The surface roughness was described using standard contact profilometer as well as novel method, fractal analysis. It was found that the different surface preparation resulted in a difference in roughness with a parameter increase of at least one order of magnitude for the ground sample as compared with the polished sample. The oxidation test was performed in a horizontal tube furnace. Post-exposure analyses including glow discharge optical emission spectrometry (GD-OES) and scanning electron microscopy (SEM), which revealed that grinding lowers the oxidation kinetics of IN 625 from 1.76 × 10−12 cm2·s−1, obtained for polished sample, to 9.04 × 10−13 cm2·s−1. It was found that surface preparation influences the oxide scale composition and morphology. The hypothesis explaining the mechanism responsible for the changes in oxidation behavior is proposed as well.

The Influence of Substrate Roughness on the Surface Condition of WC-Co Coatings Obtained Using the Supersonic Method

2016 ◽  
Vol 246 ◽  
pp. 139-142
Author(s):  
Jacek Mendala ◽  
Krzysztof Szymański
Keyword(s):  
Protective Coatings ◽  
Surface Condition ◽  
Thermal Spraying ◽  
Surface Profile ◽  
Surface Preparation ◽  
Substrate Roughness ◽  
Coating Materials ◽  
Influence Of Substrate ◽  
Selection Of ◽  
Effect Of Surface

Thermal spraying process is one of the main methods of obtaining the protective coatings. Coating quality largely depends on the proper selection of coating materials, technology and spraying equipment and the method of substrate preparation. The article presents the problem of the effect of surface preparation process on selected properties of the coating produced by supersonic thermal spraying – HVOF. Blast cleaning and supersonic thermal spraying processes were characterized. The influence of blasting parameters on the resulting surface profile and selected properties of the coating, such as roughness, porosity and structure were determined by means of surface profilometry, light microscopy and digital image analysis.

Effect of surface roughness of Chinese sub-bituminous coal on the kinetics of three-phase contact formation

Fuel ◽  
2018 ◽  
Vol 216 ◽  
pp. 531-537 ◽  
Author(s):  
Shiwei Wang ◽  
Jifeng Guo ◽  
Longfei Tang ◽  
Huan He ◽  
Xiuxiang Tao
Keyword(s):  
Surface Roughness ◽  
Bituminous Coal ◽  
Phase Contact ◽  
Contact Formation ◽  
Three Phase ◽  
Kinetics Of ◽  
Effect Of Surface
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