Comparison and Analysis of Sodium Silicate and Epoxy Bonded NdFeB Magnets

Abstract:

Sodium silicate bonded and epoxy bonded magnetic NdFeB materials are fabricated, respectively. The magnetic properties, temperature coefficient, heat-corrosion and compressive strength of both bonded magnets are investigated. Results reveal that sodium silicate bonded magnet has a similar comprehensive property to epoxy bonded one. Compared to the epoxy bonded magnets, the sodium silicate bonded NdFeB has better temperature coefficient between 20 and 100 °C. The α value of the sodium silicate bonded NdFeB is-0.127 %/°C while the β value is-0.275 %/°C between 20 and 200 °C. DSC thermogram shows that sodium silicate as a bonder in magnet could exist at a higher temperature (above 1000 °C), which is far bigger than the curie point of NdFeB magnet powder. The weight gains of sodium silicate bonded magnet obtained in heat-corrosion resistance test are smaller than those of epoxy bonded one. Compressive strength test shows that sodium silicate bonded magnet has a larger compressive strength (35 MPa) than that of epoxy bonded magnet (27 MPa). Compared to the epoxy, the sodium silicate as bonder in the bonded magnet shows more compact. As a result, the sodium silicate bonded NdFeB bears better magnetic properties, temperature coefficient, heat-corrosion resistant and compressive strength.

• Periodical: Materials Science Forum (Volume 852)
• Pages: 136-141
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.852.136
• Online since: April 2016
• Authors: Yu Xia Yin*, Rui Jin Hu, Wei Qiang Liu, Ming Yue, Zhi Chao Zhen
• Keywords: Bonded NdFeB Magnet, Compressive Strength, Epoxy, Heat-Corrosion, Sodium Silicate

References

[1] M. Itoh, M. Masuda, S. Suzuki, K. Machida. Recycling of rare earth sintered magnets as isotropic bonded magnets by melt-spinning. Journal of Alloys and Compounds (2004) 374: 393-396.

DOI: 10.1016/j.jallcom.2003.11.030

[2] M. Yue, M. Tian, J. X. Zhang, D. T. Zhang, P. L. Niu, F. Yang. Microstructure and magnetic properties of anisotropic Nd-Fe-B magnets produced by spark plasma sintering technique. Materials Science and Engineering B (2006) 131: 18-21.

DOI: 10.1016/j.mseb.2005.11.010

[3] F. Yamashita, O. Yamada, S. Ohya, O. Kobayashi, M. Nakano, H. Fukunaga. Preparation of ring-shaped composite bonded magnets with continuously controlled anisotropy distribution for internal space. Journal of Physics (2010).

DOI: 10.1088/1742-6596/200/8/082027

[4] B. L. Gray. A review of magnetic composite polymers applied to microfluidic devices. Journal of the Electrochemical Society (2014) 161 (2): B3173-B3183.

DOI: 10.1149/2.023402jes

[5] F. Li. Current status of development and application for bonded Nd-Fe-B magnets. Chinese Rare Earths (1999): 63-66. [In Chinese].

[6] M. I. Qadeer, S. J. Savage, U. W. Gedde, M. S. Hedenqvist. Rheological and dynamic mechanical properties of polymer bonded magnets based on Sm2Co17 and polyamide-12. Journalof Materials Science (2014) 49: 7529-7538.

DOI: 10.1007/s10853-014-8460-4

[7] Y. Tsukada, H. Takahashi, M. Kaneko, J. Mizuguchi. Reclaim of rare earth metals from bond magnets by means of thermally activated semiconductors (TASC). Materials Transactions (2014) 55(3): 616-621.

DOI: 10.2320/matertrans.m2013418

[8] S. Mousavian, H. Ebadi-Dehaghani, D. Ashouri, H. Sadeghipour, F. Jabbari. Effect of polymer matrix on the magnetic properties of polymer bonded magnets filled Fe3O4 nanoparticles. Journal of Polymer Research (2012) 19: 9991.

DOI: 10.1007/s10965-012-9991-5

[9] C. Y. Jiang, D. P. Wang, M. J. Zhang, P. J. Li, S. G. Zhao. Effect of highly filled ferrites on non-isothermal crystallization behavior of polyamide 6 bonded ferrites. European Polymer Journal (2010) 46: 2206-2215.

DOI: 10.1016/j.eurpolymj.2010.05.002

[10] Y. X. Yin, Y. H. Zhang, Z. C. Zhen, P. K. Chu, F. Z. Lv, J. H. Ji. Thermal degradation and flame retarding characteristics of polypropylene composites incorporated with boron mud. Composites Science and Technology (2013) 85: 131-135.

DOI: 10.1016/j.compscitech.2013.06.002

[11] Y. Kang. The analysis of the solidification mechanismes& water resistance improvement accesses of the water-glass. Ceramics Science &Art (2011) (3): 10-13. [In Chinese].

[12] J. Xu. Analysis on waterglass modification mechanism using nuclear magnetic resonance spectroscopy and differential thermal analyzer. Foundry Technology (2008) 29(7): 880-883. [In Chinese].

[13] G. J. Xiong, L. Q. Chen. Behavior of water glass-polymer hybrid-modified mortars under flowing sulfuric acid solution environment. Cement and Concrete Research (2004) 34: 665-669.

DOI: 10.1016/j.cemconres.2003.10.016

[14] X. H. Zhang, W. H. Xiong, Y. F. Li, N. Song. Effect of process on the magnetic and mechanical properties of Nd-Fe-B bonded magnets. Materials and Design (2009) 30: 1386-1390.

DOI: 10.1016/j.matdes.2008.06.062

[15] D. Plusa, B. Slusarek, M. Dospial, U. Kotlarczyk T. Mydlarz. Magnetic properties of anisotropic Nd-Fe-B resin bonded magnets. Journal of Alloys and Compounds (2006) 423: 81-83.

DOI: 10.1016/j.jallcom.2005.12.051

[16] M. R. Yuan, J. T. Lu. Effect of SiO2: Na2O molar ratio of sodium silicate on corrosion resistance of silicate conversion coating. Surface and Coatings Technology (2010) 204(8): 1229-1235.

DOI: 10.1016/j.surfcoat.2009.10.024

[17] L. Schultz, J. Wecker, E. Hellstern. Formation and properties of NdFeB prepared by mechanical alloying and solid-state reaction. Journal of Applied Physics (1987) 61, 3583.

DOI: 10.1063/1.338708

[18] F. Viala, F. Joly, E. Nevalainen, M. Sagawa, K. Hiraga, K.T. Park. Improvement of coercivity of sintered NdFeB permanent magnets by heat treatment. Journal of Magnetism and Magnetic Materials (2002) 242-245: 1329-1334.

DOI: 10.1016/s0304-8853(01)00967-2

[19] X. G. Li. Development of high temperature corrosion resistant paint. Aeronautical Manufacturing Technology (2001) 1: 29-33. [In Chinese].

[20] H. L. Wang, H. H. Li, Y. X. Wang, F. Y. Yan. Preparation of macroporous ceramic from metakaolinite-based geopolymer by calcination. Ceramics International (2015) 41: 11177-11183.

DOI: 10.1016/j.ceramint.2015.05.067