Enhanced nitrogen diffusion induced by atomic attrition

Ochoa, E.A.; Figueroa, Carlos A.; Czerwiec, T.; Alvarez, F.

doi:10.1063/1.2216032

Cited by 16 publications

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“…The nominal ion beam energy and current density were fixed at 1 keV and 1.4 mA/cm 2 , respectively. According to SRIM ion bombarding simulations, the stopping distance of the ions is ~1.1 -1.8 nm [8,12]. The background chamber pressure of the deposition system is ~10 -5 Pa and the working pressure during Xe + bombardment ~1.4x10 -1 Pa. For AISI 316L, five impinging ion bombardment angles (φ = 0º, 15º, 30º, 45º and 60º) were selected for the study of the morphology after the treatment.…”

Section: Set I: Sample Preparationmentioning

confidence: 99%

“…Results reported by Abrasonis et al suggest that the effect of bombarding the material with Ar + ions after nitriding processes also has important consequences on nitrogen diffusion in austenitic stainless steel [7]. The observed changes in plasma nitriding processes are attributed to several concomitant causes such as increasing the surface roughness, stress, and creation of lattice defects, altogether improving nitrogen diffusion [8,9]. Moreover, in the nitriding process, precipitation kinetics lead to possibly complex stress profiles even considering smoothly decreasing nitrogen profiles influencing nitrogen diffusion [10].…”

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confidence: 98%

“…The observed changes in plasma nitriding processes are attributed to several concomitant causes such as increasing the surface roughness, stress, and creation of lattice defects, altogether improving nitrogen diffusion [8,9]. Moreover, in the nitriding process, precipitation kinetics lead to possibly complex stress profiles even considering smoothly decreasing nitrogen profiles influencing nitrogen diffusion [10].In this work we expand the study reported by Ochoa et al [8,9] by considering the state of the bombarded surface and the microstrain induced by Xe + bombardment in stainless and alloyed steels (AISI 316L and AISI 4140) and their influence on the nitrided layer obtained in a long time pulsed plasma nitriding process (20 hours). We remark that in standard pulsed plasma nitriding processes, Ar + ion bombardment is used in order to clean the material surface by eroding the residual oxide layer hindering nitrogen diffusion.…”

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confidence: 99%

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Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

Cucatti

Ochoa

Morales

et al. 2015

Materials Chemistry and Physics

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The modification of steel (AISI 316L and AISI 4140) surface morphology and underlying inter-crystalline grains strain due to Xe + ion bombardment are reported to affect nitrogen diffusion after a pulsed plasma nitriding process. The ion bombardment induces regular nanometric patterns and increases the roughness of the material surface. The strain induced by the noble gas bombardment is observed in depths which are orders of magnitude larger than the projectiles' stopping distance. The pre-bombarded samples show peculiar microstructures formed in the nitrided layers, modifying the in-depth hardness profile. Unlike the double nitrided layer normally obtained in austenitic stainless steel by pulsed plasma nitriding process, the Xe + pre-bombardment treatment leads to a single thick compact layer. In nitrided pre-bombarded AISI 4140 steel, the diffusion zone shows long iron nitride needleshaped precipitates, while in non-pre-bombarded samples finer precipitates are distributed in the material. Keywords: Surface modification, ion-beam bombardment, plasma nitriding, microstrain S. Cucatti et al., Materials Chemistry and Physics, Volumes 149-150, (2015), pp. 261-269 DOI http://dx.doi.org/10.1016/j.matchemphys.2014.10.015 DOI: http://dx.doi.org/10.1016/j.matchemphys.2014.10.015 2 IntroductionSurface texturing is an important method applied in various technological areas of research. Much of the current interest in surface modifications stems from the possibility of obtaining special optical, tribological, and mechanical properties in a variety of materials [1,2]. In particular, texturing steels surface by ionic bombardment (atomic attrition) is an interesting route to modify plasma nitriding processes. The efficiency of the process and the final material properties are influenced by modifications of the surface and bulk material such as roughness, defects, and stress created by ion impact. Moreover, a combination of low energy argon ion bombardment and substrate temperature modified diffusion phenomena in semiconductors [3]. Other surface modifications such as mechanical attrition ("shot-penning") generate stress, plastic deformation, defects and roughness. All these changes contribute to modify the kinetic of the surface reactions, shortening the duration of nitriding processes [4,5,6]. Results reported by Abrasonis et al. suggest that the effect of bombarding the material with Ar + ions after nitriding processes also has important consequences on nitrogen diffusion in austenitic stainless steel [7]. The observed changes in plasma nitriding processes are attributed to several concomitant causes such as increasing the surface roughness, stress, and creation of lattice defects, altogether improving nitrogen diffusion [8,9]. Moreover, in the nitriding process, precipitation kinetics lead to possibly complex stress profiles even considering smoothly decreasing nitrogen profiles influencing nitrogen diffusion [10].In this work we expand the study reported by Ochoa et al. [8,9] by considering the state of the bombard...

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Section: Set I: Sample Preparationmentioning

confidence: 99%

mentioning

confidence: 98%

mentioning

confidence: 99%

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Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

Cucatti

Ochoa

Morales

et al. 2015

Materials Chemistry and Physics

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“…A slight reduction in crystallite size of Al is caused due to stress incorporation by ion diffusion. Ion bombardment of noble gases also causes grain refinement and defects, as well as, increases the diffusion of active nitrogen species 32 . The diffusional transport during ion nitriding of Al is also accompanied by the diffusion of Al from the bulk to the surface that helps in AlN layer growth 33 .…”

Section: Xrd Analysismentioning

confidence: 99%

Structural and Mechanical Properties of Radiofrequency Ar-N2 Plasma Nitrided Aluminium

Hassan

Qayyum²,

Ahmad³

et al. 2015

Mat. Res.

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Aluminium (Al) samples were nitrided in 13.56 MHz radiofrequency (RF) discharge of 70:30 vol.% Ar:N 2 mixture at substrate temperature of 400 °C and RF power of 300 W for different fill pressures and treatment times. The nitrided samples were then characterized for their structural and mechanical properties using x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), and Vickers micro hardness testing. XRD peaks (110), (111) and (200) of aluminium nitride (AlN) and their downshift confirmed the nitride formation together with nitrogen diffusion. The metastable cubic phase (c-AlN) shows texture growth and re-orientation dependent on fill pressure and treatment time. SEM micrographs showed the surface morphology with micro-pores. EDS results showed that the nitrogen content was significantly increased with nitriding time, along with the removal of oxides. Vickers hardness of the Al surface was increased more than thrice for 30 hours nitriding.

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“…Sendo assim, tem-se o uso do feixe de íons para: Entretanto, o efeito obtido pelo bombardeamento iônico (atomic attrition) vai além da média de profundidade do aprisionamento dos íons incidentes, fato reportado também no aço 4140 (6).…”

Section: Aço Para Construção Mecânica -100cr6unclassified

Influência dos pré-tratamentos de bombardeamento com íons de Xe<sup>+</sup> e nitretação iônica no desgaste de revestimento de TiN

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Enhanced nitrogen diffusion induced by atomic attrition

Abstract: Ion beam nitriding of single and polycrystalline austenitic stainless steel J. Appl. Phys. 97, 083531 (2005); 10.1063/1.1863455Chemical state of nitrogen in a high nitrogen face-centered-cubic phase formed on plasma source ion nitrided austenitic stainless steel

Cited by 16 publications

References 25 publications

Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

Effect of bombarding steel with Xe+ ions on the surface nanostructure and on pulsed plasma nitriding process

Structural and Mechanical Properties of Radiofrequency Ar-N2 Plasma Nitrided Aluminium

Influência dos pré-tratamentos de bombardeamento com íons de Xe<sup>+</sup> e nitretação iônica no desgaste de revestimento de TiN

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