Oxidation Mechanism of Copper at 623-1073 K

Zhu, Yongfu; Mimura, Kouji; Isshiki, Minoru

doi:10.2320/matertrans.43.2173

Cited by 137 publications

(104 citation statements)

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“…Park and Natesan [4] suggested that the decreased oxidation activation energy for pure Cu oxidized at 773-973 K is attributed to the increasing grain boundary diffusion. However, Zhu et al [10] have studied the oxidation behaviors of 4N (99.99 wt.%) Cu at 623-773 K and considered that the higher oxidation activation energy value is due to the impurity segregation or agglomeration at the grain boundary hindering the grain boundary diffusion. In light of the latter case, our results can be understood.…”

Section: Oxidation Kineticsmentioning

confidence: 99%

“…Recent papers [4][5][6][7][8][9][10] revealed that the oxidation activation energies of Cu were very different as reviewed in Table 1. As can be seen that the value of oxidation activation energy at 623-823 K for OFHC Cu [7] is 84 kJ/mol, which is higher than that of 52 kJ/mol for a 2N Cu [9] and 40 kJ/mol for a floating zone refined Cu [9][10] a 6N Cu [10].…”

Section: Introductionmentioning

confidence: 99%

“…As can be seen that the value of oxidation activation energy at 623-823 K for OFHC Cu [7] is 84 kJ/mol, which is higher than that of 52 kJ/mol for a 2N Cu [9] and 40 kJ/mol for a floating zone refined Cu [9][10] a 6N Cu [10]. Thus, it has to consider the effect of the impurity on the OR of Cu.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Alloying Element of S, Se or Te on Oxidation Resistance of Cu at 573-873 K

Zhu¹

2010

TOCORRJ

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Abstract:The influence of alloying element S, Se or Te on the oxidation resistance of pure Cu was studied by oxidizing in 0.1 MPa pure oxygen atmosphere at 573-873 K in comparison with a 6N Cu (99.9999 wt.%). The addition of S, Se or Te is found to improve the oxidation resistance of Cu remarkably. This improvement is contributed from the accumulation of alloying element at the Cu 2 O/Cu interface and segregation of alloying elements at grain boundaries in Cu 2 O.

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Section: Oxidation Kineticsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Alloying Element of S, Se or Te on Oxidation Resistance of Cu at 573-873 K

Zhu¹

2010

TOCORRJ

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“…The oxidation of Cu involves two phases: partial oxidation forms Cu 2 O (red) and total oxidation produces CuO (black). 10 The formation of these two oxides is likely accompanied by the formation of mixed oxides including Mo and Tc, which would interfere with the formation of Tc 2 O 7 and, thus, confound the separation process, which is optimized to condense Tc 2 O 7 in the cooler regions of the QT. Figure 7 shows the state of the copper support after reaction with oxygen at elevated temperature.…”

Section: Chemical Processingmentioning

confidence: 99%

A new approach for manufacturing and processing targets to produce 99mTc with cyclotrons

et al. 2017

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Vous avez des questions? Nous pouvons vous aider. Pour communiquer directement avec un auteur, consultez la première page de la revue dans laquelle son article a été publié afin de trouver ses coordonnées. Si vous n'arrivez pas à les repérer, communiquez avec nous à PublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. Questions? Contact the NRC Publications Archive team atPublicationsArchive-ArchivesPublications@nrc-cnrc.gc.ca. If you wish to email the authors directly, please see the first page of the publication for their contact information. NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. NRC Publications Record / Notice d'Archives des publications de CNRC:http://nparc.cisti-icist.nrc-cnrc.gc.ca/eng/view/object/?id=d701bd8f-9420-441b-a47d-fa15f6876c5d http://nparc.cisti-icist.nrc-cnrc.gc.ca/fra/voir/objet/?id=d701bd8f-9420-441b-a47d-fa15f6876c5dModern Physics Letters A Vol. 32, No. 17 (2017) The most important radioisotope for nuclear medicine is 99m Tc. After the supply crisis of 99 Mo starting in 2008, the availability of 99m Tc became a worldwide concern. Alternative methods for producing the medical imaging isotope 99m Tc are actively being developed around the world. The reaction 100 Mo(p, 2n) 99m Tc provides a direct route that can be incorporated into routine production in nuclear medicine centers that possess medical cyclotrons for production of other isotopes, such as those used for Positron Emission Tomography. This paper describes a new approach for manufacturing targets for the (p, 2n) nuclear reaction on 100 Mo and the foundation for the subsequent commercial separation and purification of the 99m Tc produced. Two designs of targets are presented. The targets used to produce 99m Tc are subject to a number of operational constraints.They must withstand the temperatures generated by the irradiation, accommodate temperature gradients from cooling system of the target, must be resilient and must be easily post-processed to separate the 99m Tc. After irradiation, the separation of Tc from Mo was carried out using an innovative two-step approach. The process described in this paper can be automated with modules that easily fit in standard production hot cells found in nuclear medicine facilities.

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“…1,2) However, there are some problems in fabrication process, for example, surface oxidation of copper. 3,4) Furthermore, copper base alloys are used for electrical parts such as lead frame and connector, and surface stabilization of them is required for applying them to microelectronics. Several studies on oxidation of Cu alloys have been performed, and Al, Ti and Cr have been reported to be useful as alloying elements for improving the oxidation resistance of copper.…”

Section: Introductionmentioning

confidence: 99%

Improvement in Oxidation Resistance of Cu-Al Dilute Alloys by Pre-annealing in H<SUB>2</SUB> and Ar Atmospheres

et al. 2005

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The formation of protective Al 2 O 3 thin layers on Cu-Al dilute alloys and their effect on the oxidation resistance has been investigated at high temperatures. Since selective and preferential oxidation of Al in Cu-Al alloys would take place under the very low oxygen pressures, Cu-Al (Al: 0:22 mass%) alloys were annealed at various temperatures in H 2 and/or Ar atmosphere. Continuous stable Al 2 O 3 thin layers were formed on the specimens annealed in Ar after H 2 annealing. Owing to the protective thin Al 2 O 3 layers, the high temperature oxidation rates decreased to about 1/20 to 1/40 times lower than that of pure Cu.

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Oxidation Mechanism of Copper at 623-1073 K

Cited by 137 publications

References 10 publications

Effect of Alloying Element of S, Se or Te on Oxidation Resistance of Cu at 573-873 K

Effect of Alloying Element of S, Se or Te on Oxidation Resistance of Cu at 573-873 K

A new approach for manufacturing and processing targets to produce 99mTc with cyclotrons

Improvement in Oxidation Resistance of Cu-Al Dilute Alloys by Pre-annealing in H<SUB>2</SUB> and Ar Atmospheres

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