Role of Grain Boundaries in diffusional Phenomena during Gas Nitriding of Pure Iron

Farè, S.; Lecis, N.; Brescia, E.; Mazzola, Maurizio

doi:10.1016/j.proeng.2011.04.488

Cited by 6 publications

(9 citation statements)

References 6 publications

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“…where M = D/RT is the mobility, D = D 0 exp (−Q/RT ) the coefficient of diffusion, D 0 its maximum value possible, Q the energy barrier between neighboring atomic sites, and μ = μ (1) − μ (m) . As expected from Eq.…”

Section: B Kinetics Of Diffusionmentioning

confidence: 99%

“…Assuming an ideal dilute solution, i.e., γ (1) = γ (m) = 1 and S c, and combining Eqs. (11) and (12) yields…”

Section: B Kinetics Of Diffusionmentioning

confidence: 99%

“…There are different solid-solid interfaces in crystalline materials, such as grain and twin boundaries, stacking faults or interfaces between any two arbitrary phases, and they influence the overall mass diffusion kinetics. For instance, grain boundaries can affect the rate at which thermochemical treatments, such as nitriding [1] or boriding [2] occur, or act as channels of fast diffusion for other interstitial impurities (e.g., [3][4][5]). In the context of ionic diffusion, interfaces can also act as energy barriers for atomic migrations in solid-state batteries [6,7] and proton conducting fuel cells [8].…”

Section: Introductionmentioning

confidence: 99%

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General model for the kinetics of solute diffusion at solid-solid interfaces

León-Cázares

Galindo-Nava

2021

Phys. Rev. Materials

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Solute diffusion through solid-solid interfaces is paramount to many physical processes. From a modeling point of view, the discontinuities in the energy landscape at a sharp interface represent difficulties in predicting solute diffusion that, to date, have not been solved in a consistent manner across length scales. Using an explicit finite volume method, this work is the first to derive numerical solutions to the diffusion equations at a continuum level while including discrete variations in the energy landscape at a bicrystal interface. An atomic jump equation consistent with atomistic descriptions is derived and scaled up into a compendium of model interfaces: monolayer energy barriers, monolayer interfacial traps, multilayered traps, and heterogeneous interfaces. These can track solute segregation behavior and long-range diffusion effects. We perform simulations with data for hydrogen diffusion in structural metals, of relevance to the assessment of the hydrogen embrittlement phenomenon, and point defects in electronic devices. The approach developed represents an advancement in the mathematical treatment of solute diffusion through solid-solid interfaces and an important bridge between the atomistic and macroscopic modeling of diffusion, with potential applications in a variety of fields in materials science and physics.

show abstract

Section: B Kinetics Of Diffusionmentioning

confidence: 99%

“…Assuming an ideal dilute solution, i.e., γ (1) = γ (m) = 1 and S c, and combining Eqs. (11) and (12) yields…”

Section: B Kinetics Of Diffusionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

General model for the kinetics of solute diffusion at solid-solid interfaces

León-Cázares

Galindo-Nava

2021

Phys. Rev. Materials

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“…As a typical chemical heat treatment method, gas nitriding is widely used to strengthen the surface hardness, mechanical properties, and corrosion resistance of metal materials [ 1 , 2 , 3 ]. For nitrided pure iron, a compound layer of ε-Fe 2–3 N and γ′-Fe 4 N, and a diffusion layer is formed on the surface [ 4 ]. The ε-Fe 2–3 N phase is vulnerable to embrittlement and spalling during the use of nitride components, leading to accelerated damage and wear [ 5 ].…”

Section: Introductionmentioning

confidence: 99%

The Controlled Compound Layer of Ni-Coated Nitrided Pure Iron

Shen

Zhang

et al. 2020

Nanomaterials

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In order not to sacrifice nitrided layer thickness and reduce brittle compound layer thickness, Ni-coated pretreatment was carried out with electrodeposition on a pure iron surface, followed by gas nitriding. The brittle compound layer thickness of duplex surface treated samples was reduced, and the nitrided layer thickness increased to 320 μm. The microhardness was 4 times harder, and the wear loss was reduced by 68% compared with the original material. The results indicate that Ni-coated pretreatment could effectively improve microhardness and wear resistance and realize the controlled microstructure of a brittle compound layer of pure iron without compromising nitrided layer thickness. Ni coating plays an important role in ammonia adsorption and decomposition, and in the transfer of active nitrogen atoms during nitriding.

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“…The layer formed is the compound layer of δ-TiN, ε-Ti2N , which is the diffusion layer with rich Al. The optimum result is obtained at the temperature of 800 0 C in 5 hours [8][9]. Ben Slima [10] showed that stiffening before ion and gas nitriding to the tool steel material improve the depth of white layers.…”

Section: Introductionmentioning

confidence: 99%

The Effect of Chemical Compositions of Tool Steel on the Level of White Layers Homogeneity and the Surface Hardness

Widi¹,

Wardana²,

Sujana³

2013

IJMMM

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Abstract-The process of nitriding is commonly used in electronic hardware besides the automotive components. So far, there are still gains no optimum result. The atom diffusivity homogeneity effects on the material surface mechanical characteristics are yet to be done. The effecting factors like the composition of the chemicals elements in the materials are needed to be observed. In this paper the nitriding process on three types of tool steel materials with a different chemical composition was observed. The nitriding temperature and time is 550 0C and 4 hours, respectively. The white layer formed on the surface was indentified connected to their mechanical properties. The result showed that the hardness of materials is strongly affected by the stability or the homogeneity of the white layer in the surface. The homogeneity is strongly influenced by the chemical elements composition in materials. The highest hardness level, 975.5 HV occurs at the AISI P20 which shows the most homogeneous thickness surface due to Chrom composition of 2%. The next hardness level, 751.2 HV takes place in the AISI 4340 steel with 1.4 % Cr composition, and the lowest hardness, 720.8 HV occurs at the AISI 4140 with 1.07% Chrom.

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Role of Grain Boundaries in diffusional Phenomena during Gas Nitriding of Pure Iron

Cited by 6 publications

References 6 publications

General model for the kinetics of solute diffusion at solid-solid interfaces

General model for the kinetics of solute diffusion at solid-solid interfaces

The Controlled Compound Layer of Ni-Coated Nitrided Pure Iron

The Effect of Chemical Compositions of Tool Steel on the Level of White Layers Homogeneity and the Surface Hardness

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