Graphite interlayer formation during CVD diamond coating of iron base alloys: The analogy to metal dusting

Jentsch, H.G.; Rosenbauer, Georg; Rosiwal, Stefan; Singer, Robert F.

doi:10.1002/1527-2648(200006)2:6<369::aid-adem369>3.0.co;2-8

Cited by 25 publications

(6 citation statements)

References 3 publications

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“…They identified that the steam carbon reaction process is kinetically fast enough to reach equilibrium under a flowing atmosphere and it is chiefly responsible for the catastrophic failure of the low-alloy steels. − Carbon buildup on transition metal surfaces exhibits various forms. Indeed, on iron surfaces, the magnetite has been found to produce a series of carbide species or graphitic carbons, − while recent studies on methane decomposition on a Ni surface reported that the surface carbon species can penetrate into the bulk to form graphene fibers…”

Section: Introductionmentioning

confidence: 99%

On the Mechanisms of Carbon Formation Reaction on Ni(111) Surface

et al. 2012

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The carbon formation reaction (abbreviated in this work from now on as CFR) is an industrially important chemical process. Using density functional theory, we explored the detailed mechanisms of the process on the Ni(111) surface. Four possible reaction pathways that give rise to carbon deposition on the surface were examined based on minimum energy path calculations. It was found that both the direct dissociation of CO on the surface and the pathway in which a gas phase H 2 molecule reacts with an adsorbed CO molecule to produce a gas phase water molecule and a C adatom are kinetically difficult due to the high activation energies. It was identified that the rate limiting step along the reaction pathway is CO* + 2H* → HCO* + H*. Comparison of the calculated energetic profiles of the CFR process on both the Ni( 111) and the γ-Fe(111) surfaces was also made. Both the H atom and the CO moiety exhibit high mobility on the surfaces after adsorption, which allows them to readily react with various surface species. We found that the Ni(111) surface is capable of blocking the sequential surface reactions in the early stages, in contrast to the surface processes on the γ-Fe(111) surface. This suggests that nickel is more resistant against carbon formation than iron, which is consistent with experimental observations.

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Section: Introductionmentioning

confidence: 99%

On the Mechanisms of Carbon Formation Reaction on Ni(111) Surface

et al. 2012

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“…In these respects, coatings of ferrous materials with diamond thin films by chemical vapor deposition (CVD) 1) have been intensively investigated [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] to broaden considerably the scope of applications of diamond as well as ferrous materials. However, the diamond CVD on ferrous alloy substrates has been hardly achieved, owing to the catalytic effect of iron and the rapid diffusion coefficient of carbon in iron.…”

Section: Introductionmentioning

confidence: 99%

“…The catalytic effect leads to the graphitization of the surface, explained by the stabilization of sp 2 bonding due to the catalytic activity of the 3d shell 2) and the high vapor pressure 3,4) of iron, or the low activity of carbon (a c < 1) in the gas phase. 5) The rapid diffusion coefficient corresponding to the large solubility of carbon in iron results in the long incubation time of diamond nucleation, 3,4) indicating that diamond hardly nucleates on a ferrous substrate.…”

Section: Introductionmentioning

confidence: 99%

Direct Coating of Nanocrystalline Diamond on Steel

Tsugawa¹,

Kawaki²,

Ishihara³

et al. 2012

Jpn. J. Appl. Phys.

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Nanocrystalline diamond films have been successfully deposited on stainless steel substrates without any substrate pretreatments to promote diamond nucleation, including the formation of interlayers. A low-temperature growth technique, 400 C or lower, in microwave plasma chemical vapor deposition using a surface-wave plasma has cleared up problems in diamond growth on ferrous materials, such as the surface graphitization, long incubation time, substrate softening, and poor adhesion. The deposited nanocrystalline diamond films on stainless steel exhibit good adhesion and tribological properties, such as a high wear resistance, a low friction coefficient, and a low aggression strength, at room temperature in air without lubrication. #

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“…This fact was originally explained by two possible mechanisms: the stabilization of sp 2 bonding due to the catalytic activity of the 3d shell of iron, which promotes deposition of sp 2 bonded carbon phases [2], and the high vapor pressure of iron which leads to contamination of the growing diamond [3,4]. Jentsch et al [5] later reported that graphite formation during diamond deposition is directly related to a low activity of carbon (a c < 1) in the gas phase and does not show correlation with either a high vapor pressure of the substrate or an unpaired electron structure. An excess of carbon diffuses into the metal phase and this leads to the formation of cementite (Fe 3 C) at the surface which acts as a diffusion barrier for carbon and promotes precipitation of graphite on the surface.…”

Section: Introductionmentioning

confidence: 99%

“…An excess of carbon diffuses into the metal phase and this leads to the formation of cementite (Fe 3 C) at the surface which acts as a diffusion barrier for carbon and promotes precipitation of graphite on the surface. As cementite decomposes, metal atoms diffuse through the graphite layer and reach the surface where they catalyze the formation of graphite [4,5].…”

Section: Introductionmentioning

confidence: 99%