Paper Titles

Microstructural Refinement in a Commercial Aluminum Alloy Processed by ECAP Using a Die Channel Angle of 110 Degrees
p.3

Mechanical Behavior for some Cobalt Alloys
p.9

Focus on Carbide-Tipped Circular Saws when Cutting Stainless Steel and Special Alloys
p.13

The Sintering Mixed Powders Behavior of Triuranium Octoxide in Uranium Dioxide
p.22

The SmCo₅ Intermetallic Compound Sintering
p.29

Thermal Analysis of Heat Sinks for a Power Thyristor Module
p.38

Thermal Conductivity of Aluminum Particle Filled High Density Polyethylene Composites – Particle Size Effect
p.44

Improvement of the Magnetic Properties of Silicon Iron Alloys through Laser Irradiation and Thermal Treatments
p.50

Die Failures in Copper Hot Extrusion
p.56

HomeAdvanced Materials ResearchAdvanced Materials Research Vol. 1114The SmCo5 Intermetallic Compound Sintering

The SmCo₅ Intermetallic Compound Sintering

Article Preview

Abstract:

The SmCo₅ has three sintering stages using spheres (0.6 – 1.0 mm diameter) at temperatures between 1030 and 1200 °C. During the first stage the neck radius increases as X² ~ t for less than 1200 °C temperature, the exponent is 3 at 1200 °C. Interdiffusion is sintering mechanism for exponent of 2. Sm diffuses from inside to the surface, where it is oxidized and oxides fills the neck between the spheres. Co diffuses through the oxides. At 1200 °C the sintering mechanism is evaporation-condensation of Sm. The activation enthalpy of the first stage is 582 kJmol^-1 for temperatures above 1130 °C and 210 kJmol^-1 bellow 1130 °C, respectively. The second stage is characterized by a plateau where the neck growth is arrested. The small pores in the neck and in the sphere surface layer (formed during the first stage) shrink. When these pores disappear a continuous α-Co layer forms and the third stage starts. It is essential growth of the neck formed by dense Co layer. The law of sintering is X⁴ ~ t. The activation enthalpy (276 kJmol^-1 at temperatures above 1130 °C) closes the activation enthalpy of Co self-diffusion. This (together with the exponent of 4) suggests that the Co layer plays a role similar to that of a liquid film. Making slight changes in the chemical composition of the alloys and substituting an argon atmosphere to vacuum have no influence or stages and sintering mechanisms.

You might also be interested in these eBooks

Materials Research and Application

Info:

Periodical:

Advanced Materials Research (Volume 1114)

Pages:

29-37

DOI:

https://doi.org/10.4028/www.scientific.net/AMR.1114.29

Citation:

Cite this paper

Online since:

July 2015

Authors:

George Arghir*

Keywords:

Sintering Mechanism, SmCo₅

Export:

RIS, BibTeX

Price:

Permissions CCC:

Request Permissions

Permissions PLS:

Request Permissions

Сopyright:

© 2015 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

* - Corresponding Author

[1] Y. Hou, Z. Xu, S. Peng, C. Rong, J. P. Liu, S. Sun, A facile synthesis of SmCo5 magnets from core/shell Co/Sm2Co3 nanoparticles, Adv. Mat. 19 (2007) 3349-3352.

DOI: 10.1002/adma.200700891

[2] H. Chen, Z. Zhen, T. Todd, P. K. Chu, J. Xie, Nanoparticles for improving cancer diagnosis, Mat. Sci. Eng. R 74 (2013) 35-69.

[3] G. F. Goya, V. Grazu, M. R. Ibarra, Magnetic nanoparticles for cancer therapy, Curr. Nanosci. 4 (2008) 1-16.

[4] A. E. Deatsch, B. A. Evans, Heating efficiency in magnetic nanoparticle hyperthermia, J. Magn. Magn. Mat. 354 (2014) 163-172.

DOI: 10.1016/j.jmmm.2013.11.006

[5] S. March, A topical review of magnetic nanoparticles: physics and application, Fall 2013 EE519 1-15.

[6] S. V. Meschel, P. Nash, Q. N. Gao, J. C. Wang, Y. Du, Standard enthalpies of formation of some Lanthanide-Cobalt binary alloys by high temperature direct synthesis calorimetry, J. Alloys Comp. 578 (2013) 465-470.

DOI: 10.1016/j.jallcom.2013.05.162

[7] M. Doser, L. B. Beach, Hot formed SmCo5 to produce radially oriented motor magnets, IEEE Trans. Magn. MAG-X (1974) 735-738.

DOI: 10.1109/tmag.1974.1058380

[8] D. J. Michel, E. Ryba, Powder Metallurgy Technique for the preparation of HoZn2 samples, J. Less Comm. Met. 16 (1968) 74-76.

DOI: 10.1016/0022-5088(68)90159-8

[9] K. J. Strnat, Cobalt-rare earth alloys as promising new permanent magnet materials, Cobalt, 36 (1967) 133-143.

[10] A. Traff, P. Skotte, Isostatic pressing of ceramic materials, methods, and trends, Powder Metall. Int. 8 (1976) 65-68.

[11] D. K. Das, Twenty million energy product samarium-cobalt magnet, IEEE Trans. Magn. MAG-V (1969) 214-216.

DOI: 10.1109/tmag.1969.1066489

[12] D. K. Das, Influence on sintering temperature on magnetic properties of samarium-cobalt magnets, IEEE Trans. Magn. MAG-VII (1971) 432-435.

DOI: 10.1109/tmag.1971.1067144

[13] K. H. J. Buschow, P. A. Naastepad, F. F. Westendorp, Preparation of SmCo5 permanent magnets, J. Appl. Phys. 40 (1969).

DOI: 10.1063/1.1657138

[14] R. E. Cech, Sintering of the die-pressed Co5Sm magnets, J. Appl. Phys. 41 (1970) 32-35.

[15] R. E. Johnson, C. J. Fellows, Preparation of rare earth-cobalt permanent magnets by a simplified technique, Cobalt 52 (1971) 191-196.

[16] M. G. Benz, D. L. Martin, Mechanism of sintering in cobalt-rare earth permanent magnet alloys, J. Appl. Phys. 42 (1972) 3165-3170.

DOI: 10.1063/1.1661680

[17] D. L. Martin, M, G. Benz, Cobalt-rare earth permanent magnet alloys, Cobalt 50 (1971) 11-15.

[18] G. H. Gessinger, E. Lamotte, K. Bachman, On the sintering mechanism of SmCo5 powders, IEEE Trans. Magn. MAG-VIII (1972) 557-559.

[19] G. H. Gessinger, E. Lamotte, Der Sintermechanismus von Samarium-Kobalt-Legierungen, Zeit. Metallk. 64 (1973) 771-775.

DOI: 10.1515/ijmr-1973-641105

[20] P. A. Naastepad, F. J. A. Broeder, R. J. K. Wassink, Technology of SmCo5 magnets, Powder Metall. Int. 5 (1973) 61-65.

[21] P. J. Jorgensen, R. W. Bartelett, Solid-phase sintering of SmCo5, J. Less Comm. Met. 37 (1974) 205-212.

[22] J. W. Walkiewitz, J. S. Winston, M. M. Wong, The effect of composition on the magnet properties of Sm-Co alloys, Proc. Ninth Rare Earth Res. Conf. Blacksburg Virginia (1971) 242-251.

[23] R. Kamm, M. Steinberg, J. Wulff, Plastic deformation in metal-powder compacts, Trans. Amer. Inst. Mining Metall. Eng., Inst. Metal Div. 171 (1947) 439-456.

[24] G. C. Kuczynski, Study of the sintering of glass, J. Appl. Phys. 20 (1949) 1160-1163.

[25] G. C. Kuczynski, Fundamentals in sintering theory, Proc. Eighteen Sagramore Army Mat. Res. Conf., Syracuse Univ. Press (1972) 101-117.

[26] G. C. Kuczynski, Physics and chemistry of sintering, Adv. Colloid Interface Sci. 3 (1972) 275-330.

[27] J. Tournon, G. C. Kuczynski, Diffusion coefficients from sintering of Au-Cu alloy wires, Scripta Metall. 5 (1976) 65-68.

DOI: 10.1016/0036-9748(71)90206-7

[28] W. D. Kingery, M. Berg, Study of the initial stages of solid sintering by viscous flow, evaporation-condensation and selfdiffusion, J. Appl. Phys. 26 (1955) 1205-1212.

DOI: 10.1063/1.1721874

[29] R. L. Coble, Initial sintering of alumina and hematite, J. Amer. Cer. Soc. 16 (1958) 55-58.

[30] F. V. Lenel, The mechanisms of sintering of the early stages of sintering, Powder Metall. High Perfor. Appl., Proc. Eighteen Sagramore Army Mat. Res. Conf., Syracuse Univ. Press (1972) 119-137.

[31] M. F. Asby, A first report on sintering diagrams, Acta Metall. 22 (1974) 275-289.

[32] D. L. Johnson, New method of obtaining volume, grain-boundary and surface diffusion coefficients from sintering data, J. Appl. Phys. 40 (1969) 192-200.

DOI: 10.1063/1.1657030

[33] D. L. Johnson, Recent development in the analyses of sintering kinetics, Proc. Eighteen Sagramore Army Mat. Res. Conf., Syracuse Univ. Press (1972) 139-149.

[34] H. E. Exner, C. Muller, Particle Rearrangement and Pore Space Coarsening During Solid-State Sintering, J. Amer. Cer. Soc. 92 (1976) 1384-1390.

DOI: 10.1111/j.1551-2916.2009.02978.x

[35] J. S. Lee, L. Klinger, E. Rabkin, Particle rearrangement during sintering of heterogeneous powder mixtures: A combined experimental and theoretical study, Acta Mater. 60 (2012) 123-130.

DOI: 10.1016/j.actamat.2011.09.048

[36] G. C. Kuczynski, Theory of residual porosity in powder compacts, Powder Metall. 12 (1963) 1-16.

DOI: 10.1179/pom.1963.6.12.001

[37] P. Saravanan, R. Gopalan, D. Sivaprahasam, V. Chandrasekaran, Effect of sintering temperature on the structure and magnetic properties of SmCo5/Fe nanocomposite magnets by spark sintering, Intermetall. 42 (2013) 199-204.

DOI: 10.1016/j.intermet.2013.05.011

[38] C. C. Herrick, The vapor pressure and heat of sublimation of samarium, J. Less Comm. Met. 7 (1964) 330-335.

DOI: 10.1016/0022-5088(64)90076-1

[39] W. L. Bond, Making small spheres, Rev. Sci. Instr. 22 (1951) 344-345.

[40] Y. Khan, A contribution to the Sm-Co phase diagram, Acta Crystall. B 30 (1974) 861-864.

[41] A. E. Ray, A review of the binary rare earth-cobalt alloy systems, Cobalt (1974) 13-20.

[42] K. L. Williams, R. W. Bartelett, P. J. Jorgensen, Contribution to the Sm-Co phase diagram, J. Less Comm. Met. 37 (1974) 174-176.

[43] G. C. Kuczynski, G. Matsumura, B. D. Cullity, Segregation in homogeneous alloys during sintering, Acta Metall. 7 (1960) 209-215.

DOI: 10.1016/0001-6160(60)90129-2

[44] A. M. Gadall, H. W. Hennicke, Sintering of barium hexaferrite, Powder Metall. Int. 8 (1976) 61-64.

[45] G. C. Kuczynski, Sintering in multicomponent systems, Sintering and Related Phenomenon, Proc. Int. Conf., June 1965, Univ. Notre Dame, G. C. Kuczynski et al. Editors, New York, Gordon and Breach Sci. Publ. (1967) 685-714.

[46] G. C. Kuczynski, Formation of oxides by sintering of component oxides, Proc. Int. Conf. Ferrites, Japan, July (1970) 87-95.

[47] V. J. Lee, G. Parravano, Sintering reactions of zinc oxide, J. Appl. Phys. 30 (1959) 1735-1740.

[48] G. Parravano, Chemical sintering of berthollide compounds, Reactivity of Solids, Proc. Fourth Int. Symp. Reactivity of Solids, Amsterdam, 1960, deBoer at al. Ed. Elsevier Publ. Co. Amsterdam, (1961) 83-90.

[49] C. J. Meechan, Adv. Nuclear Eng. 2 (1957) 209.

[50] W. J. Moore, E. L. Williams, Diffusion of zinc and oxygen in zinc oxide, Crystal Imperfections and the Chemical Reactivity of Solids, Discus. Faraday Soc., London 28 (1959) 86-93.

DOI: 10.1039/df9592800086

[51] R. W. Bartelett, P. J. Jorgensen, Microstructure and growth kinetics of the fibrous subscale formed by internal oxidation of SmCo5, Metall. Trans. 5 (1974) 335-361.

DOI: 10.1007/bf02644102

[52] R. W. Bartelett, P. J. Jorgensen, Microstructural changes in SmCo5 caused by oxygen sinter-annealing and thermal aging, J. Less Com. Met. 37 (1974) 21-34.

DOI: 10.1016/0022-5088(74)90005-8

[53] G. C. Kuczynski, The mechanism of densification during sintering of metallic particles, Acta Metall. 4 (1965) 58-61.

[54] R. C. Weast, Handbook of Chemistry and Physics, Cleveland, Ohio, The Chemical Rubber Company, 1972-1973, F-49.

[55] L. Jahn, V. Ivanoz, R. Schumann, M. Loewenhaupt, Influence of the initial temperature on the thermal remagnetization of SmCo5 sintered magnets, J. Magn. Magn. Mat. 256 (2003) 41-45.

DOI: 10.1016/s0304-8853(02)00019-7

[56] W. Szmaja, Studies of the domain structure of anisotropic sintered SmCo5 permanent magnets, J. Magn. Magn. Mat. 311 (2007) 469-480.

DOI: 10.1016/j.jmmm.2006.10.721