Oxidation Behavior and Structure Stability at 1250 °C of Chromium-Rich TaC-Containing Cast Alloys Based on Nickel and Cobalt

Berthod, Patrice; Gomis, Jean‐Paul; Medjahdi, Ghouti

doi:10.1007/s11661-020-05828-8

Cited by 3 publications

(3 citation statements)

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“…Indeed TaC also presents this morphology in creep-resistant Co(Ni)based industrial superalloys [17][18][19] and in Fe-based alloys. [20,21] This can be also said for HfC recently obtained in significant quantity in Co-based [22] and Ni-based [23] academic alloys. The carbides of titanium have the advantage of a lower density by comparison with the ones of the other monocarbides which involve much heavier metallic elements such as Ta or Hf, with as consequence a slight lowering of the volume mass of the whole alloy.…”

Section: Introductionmentioning

confidence: 72%

“…Can this element take part to the constitution of an interfacial oxide separating alloy and the chromia scale with good or bad influence of the adherence of the later (as the CrTaO 4 formation which occurs for tantalum-containing alloys [22] )?…”

Section: Introductionmentioning

confidence: 99%

“…If the carbides network is composed of a great part of TiC, have these ones a tendency to disappear from the oxidation front to develop a carbide-free zone as TaC [22] ? Or not as HfC [23] ?…”

Section: Introductionmentioning

confidence: 99%

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Influence of Ti and Co/Ni Ratio on the Oxidation at 1200 °C of Chromium-Containing {Ni, Co}-Based Cast Alloys

Berthod

Wora

2021

Metall Mater Trans A

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This work investigates the possible influence that titanium may have on the oxidation of {nickel and/or cobalt}-based chromium-rich alloys. It starts with the elaboration by casting of a series of alloys from pure elements, with a base element ranging from nickel only to cobalt only. To magnify these possible effects of titanium and reach the atomic equivalence with the carbon present (0.4 wt pct C) in the alloys, 1.6 wt pct Ti was introduced in the chemical composition. To amplify the oxidation process, the oxidation tests carried out in laboratory air were run at the constant temperature of 1200 °C for a rather long time (170 hours). The surface states and cross-sections were characterized by XRD, electron microscopy and EDS analyses. The results demonstrate that all the alloys (except the nickel-free cobalt-based one) resisted oxidation rather well without catastrophic evolution due to titanium. The tested Ti content led to significant internal oxidation and to an external selective oxidation producing a thin layer stick on the outer side of the chromia scale. It is supposed that this outermost TiO 2 layer may be beneficial for the oxidation behavior by the possible limitation of the deleterious over-consumption of chromium by chromia re-oxidation/volatilization. This will be later verified by further investigations combining thermogravimetry follow-up of the oxidation rate and analysis of chromium balance sheets.

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