National University of Science and Technology “MISiS”, Moscow, Russia:

V. P. Tarasov, Head of Department of Non-Ferrous Metals and Gold, Professor, e-mail: hohlova.oksana.v@misis.ru
E. S. Gorelikov, Deputy Director, Center of Manufacturing Technologies Engineering
A. V. Kutepov, Principal Engineer, Project Department, Center of Manufacturing Technologies Engineering
A. A. Stepnov, Engineer, Project Department, Center of Manufacturing Technologies Engineering

Discovery and progressive development of the higher power permanent magnetic medium is the principle aspect of magnetism exploration. Producing magnets, composed of rare-earth metals, iron and boron (REM – Fe – B), marks an epoch in the permanent magnet investigations and technologies. An energetic product, which outperforms all characteristics of preceding magnetic mediums, has been achieved in the Nd – Fe – B-based magnets. In contrast to alloys of the Nd – Fe – B system, the Sm – Co magnets combine high corrosion/ oxidation resistance and higher Curie temperature with high magnetocrystal anisotropy. The Sm – Co magnets perfectly suit for special usage in defense technologies and high-technology branches of production. Strength of soldered joints of materials based on Nd – Fe – В and Sm – Co alloys is studied. Soldering of the materials has been carried out with the use of preliminary applied copper covering, deposited by cold spraying and galvanic method. The rupture strength of the samples soldered over copper covering, obtained by cold spraying, was demonstrated to be 1.8–2.3 times higher than that of the samples, soldered over electroplating. Thermocycling of the samples within the temperature range from –50 to 150 ^oС and their corrosion tests have revealed that the soldered joints over copper covering, applied by cold spraying, are less tolerant to temperature differences, but have substantially higher corrosion stability, and at the same time their rupture strength is 1.5–2 times greater than that of the samples based on copper electroplating. Rupture strength of the soldered joint for a 5 μm thick copper covering amounts to 48 MPa, which is 3–4 higher than that of the glued joints.

This article was prepared within the framework of the Agreement No.1/2015 of July 28, 2015 between the National University of Science and Technology “MISiS” and “Research and Production Association Magneton” Joint Stock Company (Moscow, Russia), realized with the financial support according to the Resolution of the Government of the Russian Federation No. 218 dated April 09, 2010 “On measures of the state support of development of cooperation of the Russian higher educational institutions and organizations implementing complex projects to create high-technology production”.

1. Herbst J. F., Croat J. J. Neodymium – iron – boron permanent magnets. Journal of Magnetism and Magnetic Materials. 1991. Vol. 100. pp. 57–78.
2. Kablov E. N., Petrakov A. F., Piskorskiy V. P., Valeev R. A., Chabina E. B. Effect of cerium and yttrium on the magnetic properties and phase composition of materials of the Nd – Dy – Fe – Co – B system. Materialovedenie i termicheskaya obra botka metallov. 2005. No. 6. pp. 12–16.
3. Buschow K. H. J. New Developments in Hard Magnetic Materials. Reports on Progress in Physics. 1991. Vol. 54, No. 9. pp. 1123–213.
4. Beibei Zhou, Xiangbin Li, Xiaolin Liang, Gaolin Yan. 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.
5. Krishnan M., Predeep P., Sridhara Rao D. V., Prajapat C. L. High coercivity Sm – Co thin films from elemental Sm/Co multilayer deposition and their microstructural aspects. Journal of Magnetism and Magnetic Materials. 2017. Vol. 430. pp. 47–51.
6. Kobayashi K., Suzuki S., Kuno T., Urushibata K. The origin of high magnetic properties in (R,Zr)(Fe,Co)11.0 – 11.5Ti1.0 – 0.5Ny (y = 1.0–1.4 for R = Nd, y = 0 for R = Sm) compounds. Journal of Magnetism and Magnetic Materials. 2017. Vol. 426. pp. 273–278.
7. Worden K. New smart materials and structures. Properties and applications. Moscow : Tekhnosfera, 2006. 224 p.

8. Kaleta J., Wiewiórski P. Magnetovisual method for monitoring thermal demagnetization of permanent magnets used in magnetostrictive actuators. Journal of Rare Earths. 2014. Vol. 32. pp. 236–241.
9. Guoxi Xi, Lu Wang , Tingting Zhao. Magnetic and magnetostrictive properties of RE-doped Cu – Co ferrite fabricated from spent lithium-ion batteries. Journal of Magnetism and Magnetic Materials. 2017. Vol. 424. pp. 130–136.
10. Gonçalves R., Larrea A., Zheng T., Higgins M. J. Synthesis of highly magnetostrictive nanostructures and their application in a polymer-based magnetoelectric sensing device. European Polymer Journal. 2016. Vol. 84. pp. 685–692.
11. Lukina N. F., Dementeva L. A., Petrova A. P., Tyumeneva T. Yu. Properties of glues and adhesives for aeronautical engineering products. Klei. Germetiki, Tekhnologii. 2009. No. 1. pp. 14–24.
12. Soldering reference book. Third edition. Ed.: I. E. Petrunin. Moscow : Mashinostroenie, 2003. 480 p.
13. Sidorov E. V. Technical characteristics, exploitation and physical properties of modern magnetic materials and constant magnets. Vladimir : Tranzit – IKS, 2006. 38 p.