Journals →  Tsvetnye Metally →  2018 →  #7 →  Back

50th ANNIVERSARY OF PRIARGUNSKY INDUSTRIAL MINING AND CHEMICAL UNION
ArticleName The influence of gallium and copper on the corrosion properties of magnetically hard materials of the Nd – Fe – B system
DOI 10.17580/tsm.2018.07.02
ArticleAuthor Gorelikov E. S., Tarasov V. P., Kutepov A. V., Osipenkova A. A.
ArticleAuthorData

National University of Science and Technology “MISiS”, Moscow, Russia:
E. S. Gorelikov, Deputy Director, Center for Engineering of Industrial Technologies, e-mail: gorelikoves@misis.ru
V. P. Tarasov, Professor, Head of Department Non-ferrous Metals and Gold
A. V. Kutepov, Principal Engineer, Center for Engineering of Industrial Technologies
A. A. Osipenkova, Post-Graduate Student, Department of Non-ferrous Metals and Gold

Abstract

the low resistance to corrosion. One of the promising areas of research in the field of permanent magnet modification is the search for elements whose addition to Nd – Fe – B alloys contributes to increased corrosion resistance. In the work, the permissible value of gallium (Ga) and copper (Cu) content in rare earth magnets was determined, which on the one hand positively affects the corrosion resistance of magnetically hard materials (MHM), and on the other hand will allow realizing the required magnetic characteristics. On the received samples of MHM of basic structure (32% Nd, 0.5% Al, 4% Co, 1.1% B, rest — Fe), the magnetic characteristics (residual induction Br, coercive force by induction Hc b, the coercive force with respect to the magnetization jHc, the temperature coefficient of induction of TCR) and the relative fraction of the total corrosion area of the samples after the corrosion tests within 120 hours of the content of gallium and copper additives from 0.2 to 1 wt. %. It is shown that the most positive effect on the corrosion resistance of MHM samples made of base alloy is the introduction of copper, so in MHM with 1 wt. % Cu corrosion resistance is higher than that of MHM with 1 wt. % Ga by almost 25%. This can be explained by the influence of copper on the phase composition of MHM that is, reducing the amount of boroncontaining phase prone to active oxidation RFe4B, which leads to increased corrosion resistance. It has been found that the introduction of copper into MHM causes a decrease in the residual induction Br, but increases the temperature stability of MHM, by decreasing the TCR and increasing jHc. It is determined that the optimal copper content in MHM with a reduced cost price is 0.6 wt. %.
The work was carried out with the financial support of the Ministry of Education and Science of the Russian Federation in the framework of fulfilling the obligations under the Grant (No. 14.578.21.0255). Agreement from September 26, 2017 (the unique identifier of the agreement RFMEFI57817X0255).

keywords Hard magnetic materials, Nd – Fe – B magnets, corrosion resistance, coercive force, residual induction, temperature coefficient of induction, alloying, gallium, copper
References

1. Shchurin K. V., Panin I. G. Change in the properties of non-magnetic liquids in an alternating magnetic field. Informatsionno-tekhnologicheskiy vestnik. 2017. Vol. 11, No. 1. pp. 103–114.
2. Ormerod J. The physical metallurgy and processing of sintered rare-earth permanent magnets. Journal of the Less Common Metals. 1985. Vol. 111, No. 1-2. pp. 49–69.
3. Lemarchand D., Labulle B., Vigier P. Thermal Behavior of Nd–Fe–B alloys studied by T.E.M. Journal de Physique Colloques. 1988. Vol. 49 (C8). pp. C8-637–C8-638.
4. Illarionov Yu. A. Increase of temperature and corrosion resistance of magnetic systems on the basis of Nd–Fe–B alloys in operation. Elektrotekhnicheskie kompleksy i sistemy upravleniya. 2013. No. 1. pp. 8–13.
5. Willman C. J., Narasimhan K. S. V. L. Corrosion characteristics of RE – Fe – B permanent magnets. Journal of Applied Physics. 1987. Vol. 61, No. 8. pp. 3766–3768.
6. Narasimhan K. S. V. L., Willman C. J., Dulis E. J. Oxygen containing a permanent magnet alloy. Patent US, No. 4588439. Published: 13.05.1986.
7. Zhang P., Liang L., Jin J., Zhang Y., Liu X. Magnetic properties and corrosion resistance of Nd – Fe – B magnets with Nd64Co36 intergranular addition. Journal of Alloys and Compounds. 2014. Vol. 616. pp. 345–349.
8. Zhou B., Li X., Liang X., Yan G., Chen K., Yan A. Improvement of the magnetic property, thermal stability and corrosion resistance of the sintered Nd – Fe – B magnets with Dy80Al20 addition. Journal of Magnetism and Magnetic Materials. 2017. Vol. 429. pp. 257–262.
9. Kitano Y., Shimomura J., Shimotomai M., Fukuda Y., Fujita A., Ozaki Y. Analytical electron microscopy of corrosion-resistant Nd-(Fe, Co, Ni, Ti)-B magnets. Journal of Alloys and Compounds. 1993. Vol 193, No. 4. P. 245–248.
10. Isotahdon E., Huttunen-Saarivirta E., Kuokkala V.-Т. Characterization of the microstructure and corrosion performance of Ce-alloyed Nd – Fe – B magnets. Journal of Alloys and Compounds. 2017. Vol. 692. pp. 190–197.
11. Ni J., Zhou S., Jia Z., Wang C. Improvement of corrosion resistance in Nd–Fe–B sintered magnets by intergranular additions of Sn. Journal of Alloys and Compounds. 2014. Vol. 588. pp. 558–561.
12. Kuznetsov V. M. Alloying and deoxidation of Nd – Fe – B and Fe – Co – Nd – Dy by niobium, hafnium and silicon. Theses of IX All-Union Conference on permanent magnets. Suzdal, September 20–23, 1988. Moscow, 1988. 63 p.
13. GOST 18898–89. Powdered products. Methods for determining the density, oil content and porosity. Introduced: 1991–01–01.

Language of full-text russian
Full content Buy
Back