Oxydation et protection des alliages base niobium

Steinmetz, J.; Vilasi, Michel; Roques, Bernárd P.

doi:10.1051/jp4:1993952

Cited by 6 publications

(6 citation statements)

References 7 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8,9 The authors compared the corrosion behavior of Ta in molten glasses at different temperatures with other materials ͑Mo, Pt-10% Rh͒ to replace commonly used electrodes made of Inconel 690. The development of Ta-based superalloys, that have been extensively studied for high-temperature applications to replace Ni-based superalloys in the aerospace domain, [10][11][12][13] would provide adequate candidate materials for the glass industry. Furthermore, new Ni-and Co-based superalloys containing a few weight percent of Ta are also being developed for high-temperature applications for the glass industry.…”

mentioning

confidence: 99%

Kinetics and Mechanisms of Tantalum Corrosion in Glass Melts

Podor¹,

Rapin²,

Nugent³

et al. 2004

J. Electrochem. Soc.

View full text Add to dashboard Cite

The kinetics and mechanisms of corrosion of pure tantalum in three molten glasses are investigated in the 1200-1400°C temperature range by thickness loss measurements. The corrosion layers formed at the metal/glass interface, the elemental concentration profiles in the glass, and the corrosion rates are determined. Corrosion rates are reported on an Arrhenius representation for each glass. They yield to the determination of the activation energies of corrosion processes that depend on the glass composition. The limiting process is probably the diffusion of oxygen through one of the corrosion layers. The corrosion mechanisms are described in the form of successive redox reactions between the glass and the substrate. The Ta V /Ta 0 standard potential is estimated to be below Ϫ1.200 V. The formation of an intermetallic compound containing boron ͑TaB͒ as a corrosion layer is evidenced for the first time.In the course of understanding the mechanisms of metal corrosion in molten glasses, a first approach consisted of using electrochemical techniques to characterize the behavior of a few selected pure metals and superalloys in contact with molten glass. 1-7 New metals are now being tested to propose new materials and to extend vitrification technology to high temperatures ͑1200-1400°C͒.Ta is a refractory metal, the use of which in the glass industry has already been considered. 8,9 The authors compared the corrosion behavior of Ta in molten glasses at different temperatures with other materials ͑Mo, Pt-10% Rh͒ to replace commonly used electrodes made of Inconel 690. The development of Ta-based superalloys, that have been extensively studied for high-temperature applications to replace Ni-based superalloys in the aerospace domain, 10-13 would provide adequate candidate materials for the glass industry. Furthermore, new Ni-and Co-based superalloys containing a few weight percent of Ta are also being developed for high-temperature applications for the glass industry. 7,14 In these materials, Ta is present in solid solution and in carbide phases and provides good mechanical properties to the alloy. Nevertheless, these phases are quickly corroded when the alloy is immersed in molten glass.To determine whether tantalum could be a good candidate for glass technology applications, a study has been undertaken in three different glasses with simplified compositions in the 1200-1400°C temperature range. Characterization of metal pieces, corrosion products, and glass was undertaken after the immersion test to determine the material behavior in glass melt, to calculate the corrosion rates, and to characterize the corrosion processes. MaterialsMetal plates.-Ta, 99.95% purity ͑Strem Chemicals͒, initial thickness 1050 ͑Ϯ5͒ m.Glasses.-Three different borosilicate glasses were provided by industrial partners in the form of 5 mm diam pellets. Their compositions are reported in Table I. ExperimentalImmersion tests.-Ta is an easily oxidable metal at temperatures higher than 500°C, 15 and the oxide scale formed is not protective. The immersi...

show abstract

mentioning

confidence: 99%

Kinetics and Mechanisms of Tantalum Corrosion in Glass Melts

Podor¹,

Rapin²,

Nugent³

et al. 2004

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…[1][2][3] However, these alloys exhibit poor oxidation resistance and undergo rapid oxidation-induced dimensional degradation at temperatures above 900°C. [4][5][6][7] Therefore, the application of oxidation-resistant coatings becomes essential for enhancing the high-temperature capability of these alloys. Coatings based on Nb-base intermetallics such as Nb-aluminides and Nb-silicides have been reported to provide good oxidation protection to Nb alloys.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and oxidation behaviour of Fe–Cr–silicide coating on a niobium alloy

Alam

Sarin

Kumawat

et al. 2016

Materials Science and Technology

View full text Add to dashboard Cite

The cyclic oxidation performance of a Fe–Cr-modified silicide coating on Nb-alloy C-103 was evaluated in air at temperatures between 1100 and 1500°C and the microstructural changes examined. The coating was oxidation resistant and the duration of protection increased from 60 minutes at 1100°C to 255 minutes at 1500°C. The formation of the surface glassy silica layer and its ability to heal the cracks in the coating enhanced the oxidation performance at high temperatures. The outer NbSi2 layer served as a reservoir of Si and sustained the formation of the protective silica scale. Spallation of the silica scale and the concomitant depletion of the NbSi2 layer towards the regeneration of the silica scale limit the oxidation life of the coating.

show abstract

“…For higher temperatures, no metallic system is still available although efforts are made to develop Nb or Mo base alloys [2,3]. Chromium can be a candidate of interest as base to refractory alloys regarding its high melting point (1860°C) compared with Ni (1460°C), its lower density (7.15 vs. 8.90) and its thermal expansion coefficient (8.3x10 -6 K -1 ) close to the one of chromia (7.3x10 -6 K -1 ).…”

Section: Introductionmentioning

confidence: 99%

Study of the Microstructure and Oxidation Behavior of Chromium Base Alloys Strengthened by NiAl Precipitates

Royer

Mathieu

Liebaut

et al. 2008

MSF

View full text Add to dashboard Cite

In this study, chromium based alloys containing a hardening NiAl phase are investigated from 1100°C to 1300°C in air. The influence of the NiAl content and of the Al/Ni ratio on microstructure modification and on oxidation behaviour are characterized by metallography and thermogravimetry. Increasing the Al/Ni ratio leads to a higher Al content in the chromium solid solution but does not modify the amount of primary NiAl. At high temperature, and for NiAl content exceeding 16 at%, a duplex oxide layer forms at the surface of the alloys exposed in air, alumina in the inner part, and chromia in the outer part. The oxidation behavior is discussed according to oxidation profile and to the thermodynamic predominance diagram of the involved species.

show abstract

Oxydation et protection des alliages base niobium

Cited by 6 publications

References 7 publications

Kinetics and Mechanisms of Tantalum Corrosion in Glass Melts

Kinetics and Mechanisms of Tantalum Corrosion in Glass Melts

Microstructure and oxidation behaviour of Fe–Cr–silicide coating on a niobium alloy

Study of the Microstructure and Oxidation Behavior of Chromium Base Alloys Strengthened by NiAl Precipitates

Contact Info

Product

Resources

About