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The isothermal section (500°C) of the phase diagram of the Fe–Ho–V ternary system
Journal of Alloys and Compounds 287 (1999) 195–196
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The isothermal section (5008C) of the phase diagram of the Fe–Ho–V ternary system Zhang Liping*, Zhou Kaiwen, Wu Shiwei, Zhuang Yinghong Institute of Materials Science, Guangxi University, Nanning, Guangxi 53004, People’ s Republic of China Received 5 December 1998; received in revised form 19 January 1999
Abstract The isothermal section (5008C) of the phase diagram of the Fe–Ho–V ternary system was investigated by X-ray powder diffraction, differential thermal microanalysis, optical microscopy and electron probe microanalysis (EPMA) techniques. The section consists of nine single-phase regions, 16 two-phase regions and eight three-phase regions. Only one ternary compound (Fe 10 HoV2 ) was found in this isothermal section. The Fe 10 HoV2 exhibits no homogeneity range. The maximum solid solubility of holmium in a-Fe, d-FeV and V are about 1.5 at.%, 6 at.%, and 2.0 at.%, respectively. 1999 Elsevier Science S.A. All rights reserved. Keywords: Phase diagram; Isothermal section; X-ray diffraction analysis
1. Introduction
2. Experimental details
A series of novel ternary compounds of the composition RFe 10 V2 (R5Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) with the ThMn 12 structure have been investigated actively due to their potential application as permanent magnets [1–6]. No investigation of the Fe–Ho–V ternary system has yet been reported in the literature. In order to obtain information about existing compounds and the respective phase relation of Fe–Ho–V and to provide a basis for searching for rare earth permanent magnets, we studied the isothermal section of this system at 5008C. According to Ref. [7], there are four compounds in the Fe–Ho system: Fe 17 Ho 2 , Fe 23 Ho 6 , Fe 3 Ho and Fe 2 Ho. The lowest liquidus temperature in the Fe–Ho system is 8758C. Refs. [8,9] show that there is one compound FeV in the Fe–V binary system. Ref. [10] reported that the solid solubility of Ho in V is about 0.1 at.% or less at all temperatures below the melting point of V, and the maximum solubility of V in Ho at the eutectic temperature is less than 0.5 at.%, and there are no compounds in the Ho–V binary system.
The starting materials used in this work were of high purity (Fe, 99.95%; Ho, 99.95%; V, 99.9%). Alloy buttons (178 in total), each 3 g, were prepared by arc melting. To ensure homogeneity, each sample was turned and remelted three times. The weight loss during arc melting was less than 0.5%. The homogenization temperatures of the alloys were chosen on the basis of the binary phase diagrams of the Fe–Ho and Fe–V systems, and the liquidus of some representative ternary alloys that were determined by differential thermal analysis. All the alloys were sealed in a quartz tube in vacuum and annealed at 8308C for 30 days and cooled to 5008C at a rate of 10 K / h; and kept at 5008C for 7 days, then quenched into an ice / water mixture. Samples for X-ray diffraction analysis were powdered and annealed at 5008C for 7 days in small glass tubes in vacuum and subsequently quenched into liquid nitrogen. X-ray diffraction analysis was performed by a Rigaku (3015) X-ray diffractometer with Mo K a radiation and zirconium filters. By comparing and analysing the X-ray diffraction patterns of the samples annealed for different times, it was shown that the phases in the alloys had reached equilibrium, and the equilibrium state of the sample at 5008C was retained by the above heat treatment. The isothermal section was mainly determined by X-ray diffraction analysis. Some samples were examined by
*Corresponding author.
0925-8388 / 99 / $ – see front matter 1999 Elsevier Science S.A. All rights reserved. PII: S0925-8388( 99 )00040-7
196
Z. Liping et al. / Journal of Alloys and Compounds 287 (1999) 195 – 196
electron probe microanalysis (EPMA) to establish the phase boundaries in the section.
3. Results
3.1. Isothermal section at 5008 C By analysing and comparing the X-ray diffraction patterns of 178 samples and identifying the phases in each sample, the 5008C isothermal section of the phase diagram of the Fe–Ho–V ternary system was determined. The section consists of nine single-phase regions, 16 two-phase regions and eight three-phase regions, and it is shown in Fig. 1.
3.2. Phase analysis By analysing and comparing the X-ray diffraction patterns of the samples, we have confirmed the existence of five binary compounds: Fe 17 Ho 2 , Fe 23 Ho 6 , Fe 3 Ho, Fe 2 Ho, FeV found in the Ho–Fe and Fe–V systems, and one ternary compound: Fe 10 HoV2 in the isothermal section of the Fe–Ho–V ternary system at 5008C. A comparison of the X-ray diffraction data of the single phases with their powder diffraction files (PDF) led to good correspondence for a-Fe, Ho, V, Fe 23 Ho 6 , Fe 3 Ho, Fe 2 Ho, FeV. Their crystal data were in agreement with those given in Refs. [11–14]. Fe 17 Ho 2 is in good agreement with our previous work [15]. The crystal data of Fe 10 HoV2 are in agreement with those given by Haije et al. [16].
Fig. 1. Phase relationship in the ternary Fe–Ho–V system at 5008C. d, Single phase region; s, two-phase region; n, three-phase region.
3.3. Solid solubility The single-phase ranges in this isothermal section at 5008C were determined by X-ray diffraction using the phase-disappearing method and by comparing the movement of the diffraction patterns of the single phases. The solid solubility ranges of single-phase Ho, Fe 3 Ho, Fe 23 Ho 6 , Fe 17 Ho 2 are unmeasurable. The Fe 10 HoV2 exhibits no homogeneity range. From X-ray diffraction analysis, we determined the single phase range of Fe 2 Ho to extend parallel to the Fe–V side and the maximum of solid solubility of V in Fe 2 Ho is 11 at.%. By analysing and comparing the patterns, we found the composition range of FeV is from 38.0 at.% V to 70.0 at.%V, and the solubilities of V in Fe and Fe in V are about 24.0 at.% and 22.0 at.%, respectively. The maximum solid solubilities of Ho in the solid solutions of a-Fe, d-FeV and V are about 1.5, 6.0, and 2.0 at.%, respectively.
Acknowledgements This work was supported by the National Natural Science Foundation of China.
References [1] F.R. de Boer, H. Ying-Kai, D.B. de Mooij, K.H.J. Buschow, J. Less-Common Metals 135 (1987) 199. [2] R.B. Helmholdt, J.J.M. Vleggaar, K.H.J. Buschow, J. Less-Common Metals 144 (2) (1988) 209. [3] D.B. De Mooij, K.H.J. Buschow, J. Less-Common Metals 136 (1988) 207. [4] K.H.J. Buschow, J. Appl. Phys. 63 (8) (1988) 3130. [5] A. del Moral, P.A. Algarabel, C. de la Fuente, M.R. Ibarra, C. Marquina, J. Magn. Magn. Mater. 131 (1–2) (1994) 247–252. [6] R.W. Huang, Z.W. Zhang, B. Hu, J.D. Kang, Z.D. Zhang, X.K. Sun, Y.C. Chuang, J. Magn. Magn. Mater. 119 (1–2) (1993) 180–186. [7] T.B. Massalski, in: 2nd ed., Binary Alloy Phase Diagrams, Vol. 2, 1990, p. 1712. [8] M. Hansen, K. Anderko, in: 2nd ed., Constitution of Binary Alloys, McGraw-Hill, New York, 1958, pp. 729–732. [9] J.F. Smith, Metal Progr. 127 (7) (1985) 59–60. [10] J.F. Smith, in: Phase Diagrams of Binary Vanadium Alloys, ASM International, Metals Park, OH, 1989, pp. 118–119. [11] C.J. Smithells, 5th ed., Metals Reference Book, Butterworths, London, 1976. [12] K.A. Gschneidner Jr., L. Eyring, in: Handbook On the Physics and Chemistry of Rare Earths, Vol. 2, North-Holland, Amsterdam, 1979. [13] J.D.H. Donnay, H.M. Ondik, in: 3rd ed., Crystal Data, Determination Table, Vol. 2, National Standard Reference Data System (USA) and the Joint Committee on Powder Diffraction Standards (USA, 1973. [14] JCPDS-International Centre for Diffraction Data: Powder Diffraction File Inorganic Sets 1-44, 1994. [15] L. Junqin, Z. Yinghong, L. Weibo, Z. Metallkd. 84 (11) (1993) B773–775. [16] W.G. Haije, A. Spijkerman, F.R. De Boer, K. Bakker, K.H.J. Buschow, J. Less-Common Metals 162 (1990) 285–295.
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The isothermal section (5008C) of the phase diagram of the Fe–Ho–V ternary system Zhang Liping*, Zhou Kaiwen, Wu Shiwei, Zhuang Yinghong Institute of Materials Science, Guangxi University, Nanning, Guangxi 53004, People’ s Republic of China Received 5 December 1998; received in revised form 19 January 1999
Abstract The isothermal section (5008C) of the phase diagram of the Fe–Ho–V ternary system was investigated by X-ray powder diffraction, differential thermal microanalysis, optical microscopy and electron probe microanalysis (EPMA) techniques. The section consists of nine single-phase regions, 16 two-phase regions and eight three-phase regions. Only one ternary compound (Fe 10 HoV2 ) was found in this isothermal section. The Fe 10 HoV2 exhibits no homogeneity range. The maximum solid solubility of holmium in a-Fe, d-FeV and V are about 1.5 at.%, 6 at.%, and 2.0 at.%, respectively. 1999 Elsevier Science S.A. All rights reserved. Keywords: Phase diagram; Isothermal section; X-ray diffraction analysis
1. Introduction
2. Experimental details
A series of novel ternary compounds of the composition RFe 10 V2 (R5Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Lu and Y) with the ThMn 12 structure have been investigated actively due to their potential application as permanent magnets [1–6]. No investigation of the Fe–Ho–V ternary system has yet been reported in the literature. In order to obtain information about existing compounds and the respective phase relation of Fe–Ho–V and to provide a basis for searching for rare earth permanent magnets, we studied the isothermal section of this system at 5008C. According to Ref. [7], there are four compounds in the Fe–Ho system: Fe 17 Ho 2 , Fe 23 Ho 6 , Fe 3 Ho and Fe 2 Ho. The lowest liquidus temperature in the Fe–Ho system is 8758C. Refs. [8,9] show that there is one compound FeV in the Fe–V binary system. Ref. [10] reported that the solid solubility of Ho in V is about 0.1 at.% or less at all temperatures below the melting point of V, and the maximum solubility of V in Ho at the eutectic temperature is less than 0.5 at.%, and there are no compounds in the Ho–V binary system.
The starting materials used in this work were of high purity (Fe, 99.95%; Ho, 99.95%; V, 99.9%). Alloy buttons (178 in total), each 3 g, were prepared by arc melting. To ensure homogeneity, each sample was turned and remelted three times. The weight loss during arc melting was less than 0.5%. The homogenization temperatures of the alloys were chosen on the basis of the binary phase diagrams of the Fe–Ho and Fe–V systems, and the liquidus of some representative ternary alloys that were determined by differential thermal analysis. All the alloys were sealed in a quartz tube in vacuum and annealed at 8308C for 30 days and cooled to 5008C at a rate of 10 K / h; and kept at 5008C for 7 days, then quenched into an ice / water mixture. Samples for X-ray diffraction analysis were powdered and annealed at 5008C for 7 days in small glass tubes in vacuum and subsequently quenched into liquid nitrogen. X-ray diffraction analysis was performed by a Rigaku (3015) X-ray diffractometer with Mo K a radiation and zirconium filters. By comparing and analysing the X-ray diffraction patterns of the samples annealed for different times, it was shown that the phases in the alloys had reached equilibrium, and the equilibrium state of the sample at 5008C was retained by the above heat treatment. The isothermal section was mainly determined by X-ray diffraction analysis. Some samples were examined by
*Corresponding author.
0925-8388 / 99 / $ – see front matter 1999 Elsevier Science S.A. All rights reserved. PII: S0925-8388( 99 )00040-7
196
Z. Liping et al. / Journal of Alloys and Compounds 287 (1999) 195 – 196
electron probe microanalysis (EPMA) to establish the phase boundaries in the section.
3. Results
3.1. Isothermal section at 5008 C By analysing and comparing the X-ray diffraction patterns of 178 samples and identifying the phases in each sample, the 5008C isothermal section of the phase diagram of the Fe–Ho–V ternary system was determined. The section consists of nine single-phase regions, 16 two-phase regions and eight three-phase regions, and it is shown in Fig. 1.
3.2. Phase analysis By analysing and comparing the X-ray diffraction patterns of the samples, we have confirmed the existence of five binary compounds: Fe 17 Ho 2 , Fe 23 Ho 6 , Fe 3 Ho, Fe 2 Ho, FeV found in the Ho–Fe and Fe–V systems, and one ternary compound: Fe 10 HoV2 in the isothermal section of the Fe–Ho–V ternary system at 5008C. A comparison of the X-ray diffraction data of the single phases with their powder diffraction files (PDF) led to good correspondence for a-Fe, Ho, V, Fe 23 Ho 6 , Fe 3 Ho, Fe 2 Ho, FeV. Their crystal data were in agreement with those given in Refs. [11–14]. Fe 17 Ho 2 is in good agreement with our previous work [15]. The crystal data of Fe 10 HoV2 are in agreement with those given by Haije et al. [16].
Fig. 1. Phase relationship in the ternary Fe–Ho–V system at 5008C. d, Single phase region; s, two-phase region; n, three-phase region.
3.3. Solid solubility The single-phase ranges in this isothermal section at 5008C were determined by X-ray diffraction using the phase-disappearing method and by comparing the movement of the diffraction patterns of the single phases. The solid solubility ranges of single-phase Ho, Fe 3 Ho, Fe 23 Ho 6 , Fe 17 Ho 2 are unmeasurable. The Fe 10 HoV2 exhibits no homogeneity range. From X-ray diffraction analysis, we determined the single phase range of Fe 2 Ho to extend parallel to the Fe–V side and the maximum of solid solubility of V in Fe 2 Ho is 11 at.%. By analysing and comparing the patterns, we found the composition range of FeV is from 38.0 at.% V to 70.0 at.%V, and the solubilities of V in Fe and Fe in V are about 24.0 at.% and 22.0 at.%, respectively. The maximum solid solubilities of Ho in the solid solutions of a-Fe, d-FeV and V are about 1.5, 6.0, and 2.0 at.%, respectively.
Acknowledgements This work was supported by the National Natural Science Foundation of China.
References [1] F.R. de Boer, H. Ying-Kai, D.B. de Mooij, K.H.J. Buschow, J. Less-Common Metals 135 (1987) 199. [2] R.B. Helmholdt, J.J.M. Vleggaar, K.H.J. Buschow, J. Less-Common Metals 144 (2) (1988) 209. [3] D.B. De Mooij, K.H.J. Buschow, J. Less-Common Metals 136 (1988) 207. [4] K.H.J. Buschow, J. Appl. Phys. 63 (8) (1988) 3130. [5] A. del Moral, P.A. Algarabel, C. de la Fuente, M.R. Ibarra, C. Marquina, J. Magn. Magn. Mater. 131 (1–2) (1994) 247–252. [6] R.W. Huang, Z.W. Zhang, B. Hu, J.D. Kang, Z.D. Zhang, X.K. Sun, Y.C. Chuang, J. Magn. Magn. Mater. 119 (1–2) (1993) 180–186. [7] T.B. Massalski, in: 2nd ed., Binary Alloy Phase Diagrams, Vol. 2, 1990, p. 1712. [8] M. Hansen, K. Anderko, in: 2nd ed., Constitution of Binary Alloys, McGraw-Hill, New York, 1958, pp. 729–732. [9] J.F. Smith, Metal Progr. 127 (7) (1985) 59–60. [10] J.F. Smith, in: Phase Diagrams of Binary Vanadium Alloys, ASM International, Metals Park, OH, 1989, pp. 118–119. [11] C.J. Smithells, 5th ed., Metals Reference Book, Butterworths, London, 1976. [12] K.A. Gschneidner Jr., L. Eyring, in: Handbook On the Physics and Chemistry of Rare Earths, Vol. 2, North-Holland, Amsterdam, 1979. [13] J.D.H. Donnay, H.M. Ondik, in: 3rd ed., Crystal Data, Determination Table, Vol. 2, National Standard Reference Data System (USA) and the Joint Committee on Powder Diffraction Standards (USA, 1973. [14] JCPDS-International Centre for Diffraction Data: Powder Diffraction File Inorganic Sets 1-44, 1994. [15] L. Junqin, Z. Yinghong, L. Weibo, Z. Metallkd. 84 (11) (1993) B773–775. [16] W.G. Haije, A. Spijkerman, F.R. De Boer, K. Bakker, K.H.J. Buschow, J. Less-Common Metals 162 (1990) 285–295.