Hostname: page-component-848d4c4894-xm8r8 Total loading time: 0 Render date: 2024-06-19T12:27:40.008Z Has data issue: false hasContentIssue false
  • English
  • Français

Phase transformation in ball-milled iron-rich Sm–Fe(–C) powders

Published online by Cambridge University Press:  31 January 2011

O. Mao ,
Z. Altounian ,
J. O. Ström-Olsen  and
Jun Yang
O. Mao
Affiliation:
Centre for the Physics of Materials, Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8
Z. Altounian
Affiliation:
Centre for the Physics of Materials, Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8
J. O. Ström-Olsen
Affiliation:
Centre for the Physics of Materials, Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8
Jun Yang
Affiliation:
Centre for the Physics of Materials, Department of Physics, McGill University, Montréal, Québec, Canada H3A 2T8
Get access

Abstract

Two intermetallic phases, R2Fe17 carbide and R2Fe14C, which are promising candidates for permanent magnets, are formed in the iron-rich R–Fe–C ternary alloy system (R = rare earths). Using x-ray diffraction and thermomagnetometry the phase formation, transformation, and thermodynamic relations between the two structures, prepared by high energy ball milling, are studied quantitatively for R = Sm. The results lead to a free energy diagram for the pseudobinary system of Sm2Fe17 and C. A maximum equilibrium carbon content, xc, has been established for the carbide Sm2Fe17Cx and its temperature dependence determined. Beyond the equilibrium concentration, Sm2Fe17Cx transforms into a mixture of Sm2Fe17Cxc, Sm2Fe14C, and α–Fe. Although not thermodynamically stable, Sm2Fe17Cx can still be formed through nonequilibrium processes by being kinetically favored over the stable phase(s). This feature is important for the production of Sm–Fe–C-based permanent magnets.

Type
Articles
Information
Journal of Materials Research , Volume 14 , Issue 3 , March 1999 , pp. 750 - 762
Copyright
Copyright © Materials Research Society 1999

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1.Supermagnets, Hard Magnetic Materials, edited by Long, G. J. and Grandjean, F. (Kluwer Academic Publishers, The Netherlands, 1991).CrossRefGoogle Scholar
2.Buschow, K. H. J., Rep. Prog. Phys. 54, 1123 (1991).CrossRefGoogle Scholar
3.Stadelmaier, H. H. and Park, H. K., Z. Metallkd. 72, 417 (1981).Google Scholar
4.Buschow, K. J., de Mooij, D. B., and Denissen, C. J. M., Less-Common Met. 141, L15 (1988).CrossRefGoogle Scholar
5.de Mooij, D.B. and Buschow, K.H.J, J. Less-Common Met. 142, 349 (1988).CrossRefGoogle Scholar
6.Coey, J. M. D. and Sun, H., J. Magn. Magn. Mater. 87, L251 (1990).CrossRefGoogle Scholar
7.Coey, J. M. D., Sun, H., Otani, Y., and Hurley, D. P. F., J. Magn. Magn. Mater. 98, 76 (1991).CrossRefGoogle Scholar
8.Mao, O., Altounian, Z., Yang, J., and Ström-Olsen, J. O., J. Appl. Phys. 79, 5536 (1996).CrossRefGoogle Scholar
9.Mao, O., Altounian, Z., Ström-Olsen, J. O., Yang, J., and Chen, X., IEEE Trans. Magn. 32, 4413 (1996).CrossRefGoogle Scholar
10. The peritectoidal and transformation from Sm2Fe14C to Sm2Fe17 carbide involves other phases, such as SmFeC and a– Fe, depending on the composition of the Sm-Fe-C alloy.Google Scholar
11.Mao, O., Altounian, Z., and Ström-Olsen, J.O., Rev. Sci. Instrum. 68, 2438 (1997).CrossRefGoogle Scholar
12.Wertheim, G. K., Butler, M. A., West, K. W. and Buchanan, N. D. E., Rev. Sci. Instrum. 11, 1369 (1974).CrossRefGoogle Scholar
13.Klug, H. P. and Alexander, L. E., X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials (Wiley-Interscience Publication, New York, 1974).Google Scholar
14.Mao, O., Ström-Olsen, J.O., Altounian, Z., and Yang, J., J. Appl. Phys. 79, 4619 (1996).CrossRefGoogle Scholar
15.Smith, P.A.I and McCormick, P. G., Scr. Met. Mater. 26, 485 (1992).CrossRefGoogle Scholar
16.Alonso, T., Yang, H., Liu, Y., and McCormick, P. G., Appl. Phys. Lett. 60, 833 (1992).CrossRefGoogle Scholar
17.Murillo, N., Gonzalez, J., Ceollada, F., Matin, V. E., Gonzalez, J. M., and Schultz, L., IEEE Trans. Magn. 29, 2857 (1993).CrossRefGoogle Scholar
18.Gerasimov, K. B., Gusev, A.A., Ivanov, E. Y., and Boldyrev, V.V., J. Mater. Sci. 26, 2495 (1991).CrossRefGoogle Scholar
19.Fecht, H. J., Hellstern, E., Fu, Z., and Johnson, W. L., Metall. Trans. A 21A, 2333 (1990).CrossRefGoogle Scholar
20. A g-atom is used to denote a mole of atoms without distinguishing their species. For example, one mole of Sm2Fe17 has 19 units of g-atom.Google Scholar
21.Jayarman, A., Phys. Rev. 139, A 690 (1965).CrossRefGoogle Scholar
22.Johansson, B. and Rosengren, A., Phys. Rev. B 11, 2836 (1971).CrossRefGoogle Scholar
23.Altounian, Z., Guo-Hua, T., and Ström-Olsen, J.O., J. Appl. Phys. 53, 4755 (1982).CrossRefGoogle Scholar
24.Egami, T., Ann. N.Y. Acad. Sci. 371, 238 (1981).CrossRefGoogle Scholar
25.Buschow, K. H. J., Mater. Sci. Rep. 1, 1 (1977).CrossRefGoogle Scholar
26.Gschneider, K. A. Jr, and Calderwood, F.W., Bull. Alloy Phase Diagrams 7, 421 (1971).CrossRefGoogle Scholar
27.Spedding, F. H., Gschneider, K. A. Jr, and Daane, A. H., J. Am. Chem. Soc. 80, 4499 (1958).CrossRefGoogle Scholar
28.Katter, M., Wecker, J., and Schultz, L., J. Appl. Phys. 70, 3188 (1991).CrossRefGoogle Scholar
29.Buschow, K. H. J., in Supermagnets, Hard Magnetic Materials, edited by Long, G. J. and Grandjean, F. (Kluwer Academic Publishers, The Netherlands, 1991), p. 527.CrossRefGoogle Scholar
30. SmCy is an interstitial compound of the NaCl-type structure, where Sm atoms form the fcc structure and C atoms are non-stoichiometric and occupy the octahedral interstitial sites in the fcc structure. Such nonstoichiometric interstitial compound is common between the rare earth metals and nitrogen or oxygen D. We therefore speculate that the metastable SmCy may be stabilized by absorbing oxygen or nitrogen during annealing.Google Scholar
31. The primitive unit cell of the GdFeC-type structure is hexagonal. However, the space group and the atomic positions in the structure are unknown.Google Scholar
32.Mao, O., Ph.D. Thesis, McGill University, Montreal (1997).Google Scholar
33.Shen, B.G., Kong, L. S., Wang, F.W., and Cao, L., Appl. Phys. Lett. 63, 2288 (1993).CrossRefGoogle Scholar
34.Shen, B.G., Kong, L. S., Wang, F.W., Cao, L., and Zhan, W. S., J. Appl. Phys. 75, 6253 (1994).CrossRefGoogle Scholar
35.Cheng, Z.H., Shen, B.G., Wang, F.W., Zhang, J.X., Gong, H. Y., and Zhao, J. G., J. Phys.: Condens. Matter 6, L185 (1994).Google Scholar
36.Cao, L., Müller, K. H., Handstein, A., Grünberger, W., Neu, V., and Schultz, L., J. Phys. D: Appl. Phys. 29, 271 (1996).CrossRefGoogle Scholar
37.Ding, J. and Rosenberg, M., J. Less-Common Met. 166, 313 (1990).CrossRefGoogle Scholar
38. The difference between the heating and cooling scans may be caused by the subtle change in the magnetic exchange coupling between the ultrafine grains of the 2–17 carbide and Sm2Fe14C.Google Scholar
39.Skomski, R., Murray, C., Brennan, S., and Coey, J. M. D., J. Appl. Phys. 73, 6940 (1993).CrossRefGoogle Scholar
40.Helmholt, R.B. and Buschow, K.H.J, J. Less-Common Met. 155, 15 (1985).CrossRefGoogle Scholar
41.Isnard, O., Miraglia, S., Sougeyroux, J. L., Fruchart, D., and Pannetier, J., Phys. Rev. B 45, 2920 (1992).CrossRefGoogle Scholar
42.Kuhrt, C., Cerva, H., and Schultz, L., Appl. Phys. Lett. 64, 6026 (1994).CrossRefGoogle Scholar