AI-Bi Co-Fe A1-Bi (continued)

Provisional

Table 6 Fitted Thermodynamic Parameters for the AI-Bi System

Lattice stability terms ~ L = 0

~ = 0 ~ -10792 + l l .56T(a,b) 0 (Bi) GB~ = - 11297 + 20.744 T(a, b)

Interactions A L = 30972.9 - 6.878 T{a) B L = 17612.5 - 7.514T(a) C L = 13 121.5 - 8.642 T(a) D L = 2629.5 -- 0.723 T(a)

(a) T is in kelvin. (b) Treated as line compounds.

Cited References 1892Wri: C. R. A. Wright, "On Certain Aluminum Alloys", J. Soc.

Chem. Ind., 11,492-494 (1892). (Equi Diagram; Experimental) 1894Wri: C. R. A. Wright, "The Composition and Constitution of

Certain Alloys", J. Soc. Chem. Ind., 13, 1014-1017 (1894). (Equi Diagram; Experimental)

02Cam: W. Campbell and J. A. Mathews, "Alloys of Al", J. Am. Chem. Soc., 24, 253-266 (1902). (Equi Diagram; Experimental)

04Pec: H. Pecheux, "Alloys of A1 with Bi and Mg", C.R. Acad. Sci. (Paris), 138, 1501-1503 (1904) in French. (Equi Diagram; Experimental)

06Gwy: A.G.C. Gwyer, "AI-Bi and A1-Sn Alloys", Z. Anorg. Chem., 49, 311-319 (1906) in German. (Equi Diagram; Experi- mental)

06Pec: H. Pecheux, "Pyrometric Determination of the Melting Points of A1 Alloyed with Pb and Bi", C.R. Acad. Sci. (Paris), 143, 397-398 (1906) in French. (Equi Diagram; Experimental)

31Han: M. Hansen and J. Blumenthal, "On the Binary Systems of A1 with Cd, Pb, and Bi", Metallwirt., 10, 925-927 (1931) in German. (Equi Diagram; Experimental).

*39Kern: L.W. Kempf and K.R. van Horn, "Solubility of Pb and Bi in Liquid A1 and A1-Cu Alloys", Trans. Met. Soc. AIME, 133, 81-92 (1939). (Equi Diagram; Experimental)

63Cam: A.N. Campbell and J. Winkler, "The System A1-Sb-Bi",

Can. J. Chem. Eng., 41,743-749 (1963). (Equi Diagram; Experi- mental)

63Wit: F. E. Wittig and G. Keil, "Heat of Mixing of Liquid A1 with the B-Metals Zn, Cd, In, Th, Sn, Pb, and Bi", Z. Metallkd., 54, 576-590 (1963) in German. (Equi Diagram, Thermo; Experi- mental)

*64Wil" T.C. Wilder and J.F. Elliott, "Thermodynamic Studies of Ternary Liquid Metallic Systems Containing Miscibility Gap", J. Etectrochem. Soc., 111,352-362 (1964). (Equi Diagram, Thermo; Experimental)

*65Obe: C.F. Obenchain and R. E. Balzhiser, "Interaction of Ca, Sr, and Ba with the Liquid Bi-A1 and Pb-A1 Binary Systems", Electrochem. Technol., 3, 221-227 (1965). (Equi Diagram; Experimental)

*65Wee: J. R. Weeks, "Liquidus Curves of Nineteen Dilute Binary Alloys of Bi", Trans. ASM, 58, 302-322 (1965). (Equi Diagram; Experimental)

66Day: T. R. A. Davey and J. M. Floyd, "Solubility of A1 in Liquid Bi", Trans. Inst. Min. Metall. (London), 75, C123-124 (1966). (Equi Diagram; Experimental)

*66Mar: R. Martin-Garvin, G. Massart, P. Desre, and E. Bonnier, "Determination of the Equil ibrium Phase Diagram and Thermodynamic Properties of the A1-Bi System", C.R. Acad. Sci. Paris, 262, C335-338 (1966). (Equi Diagram, Thermo; Experimental)

*69Pre: B. Predel and H. Sandig, "Thermodynamic Investi- gation of the Systems A1-Bi, Al-In, and Cu-Tl", Mater. Sci. Eng., 4, 49-57 (1969) in German. (Equi Diagram, Thermo; Experimental)

77Luk" H.L. Lukas, E. Th. Henig, and B. Zimmerman, "Optimization of Phase Diagrams by a Least-Squares Method Using Simultaneously Different Types of Data", Calphad, 1, 225-236 (1977). (Thermo; Theory)

80Elh R.P. Elliott and F.A. Shunk, "The A1-Bi (Aluminum- Bismuth) System", Bull. Alloy Phase Diagrams, 1(1), 54-56 (1980). (Equi Diagram; Review)

83Cha: S. Chandra, Masters Thesis, Vanderbilt University (1983) and S. Chandra and B.D. Lichter (to be published).

83Mur: J.L. Murray, "The A[-In (Aluminum-Indium System", Bull. Alloy Phase Diagrams, 4(3), 271-278 (1983). (Thermo; Theory)

*Indicates key paper.

A1-Bi evaluation contributed by A. J. McAlister, Center for Materials Science, National Bureau of Standards. This work was jointly funded by the Defense Advanced Research Project Agency (DARPA) and the National Bureau of Standards through the Metallurgy Division and through the Office of Standard Reference Data. Literature searched through 1983. Dr. A.J. McAlister is the ASM/NBS Data Program Co-Category Editor for binary aluminum alloys.

The Co-Fe (Cobalt-Iron) System 58.9332 55.847

By T. Nishizawa and K. Ishida Tohoku University, Japan

Equilibrium Phase Diagram A number of inves t iga t ions have been made tha t a re rele- van t to the phase equi l ib r ia and phase t ransformat ions in the Co-Fe system. The const i tu t ion of the Co-Fe al loys is reproduced in Fig. 1 by adding the avai lab le informat ion to the phase d i ag ram of [Hansen, Ell iot t , Shunk, 81Riv].

S o l i d u s and Liquidus . The l i q u i d u s and so l idus re- la t ionships a re well es tabl ished. The l iquidus curve fal ls from the mel t ing point of Fe (1538 ~ to the t e m p e r a t u r e of the l'(fcc)/~(bcc) peri tect ic react ion, which was found as 1499 ~ [53Har] and 1494 ~ [70Pre]. The l iquidus con-

t inues to a m i n i m u m point a t 1476 ~ at 33.2 at.% Fe and then rises to a me l t ing point of Co a t 1495 ~ [70Pre]. Exper imenta l da t a a re plot ted in Fig. 2.

Solid Equilibrium. The ~/T equi l ib r ium is de te rmined by t he rma l a n a l y s i s [53Har] and magne t i c suscep t ib i l i ty measurements [70Fis l ] , as i l lus t ra ted in Fig. 2. The tem- pera ture of the 1,/~ t rans format ion of pure Fe is ra ised by the solution of Co. The t empe ra tu r e of the a(bcc)/~(fcc) t ransformat ion is also ra ised by Co, which indicates tha t Co stabil izes aus t en i t e nea r the A4 point , and it s tabil izes ferri te near the A3 point. The a/1, equ i l ib r ium is shown in Fig. 3 t o g e t h e r w i t h the da t a o b t a i n e d from c u r r e n t

250 Bul le t in of Alloy Phase Diagrams Vol. 5 No. 3 1984

Provisional Co-Fe

Fig. 1 Assessed Co-Fe Equilibrium Diagram

W e i g h t P e r c e n t I r o n 0 iIJ 20 30 ,t0 56 60 70 80 90 100

1700 . . . . . . . . i ' . . . . . . . i . . . . . . . . . ' . . . . . . . . . r . . . . . . . . . ] ' . . . . . . . . ~ . . . . . . ~ . . . . . ' ' . . . . . . [ ' . . . . . . . .

~tt .sim~

L 1538Oc

1 5 0 0 -

1300

O

" ~ 1100 -

9 0 0

7 0 0

L4~~

. o ~33~. , 1 4 7 6

1394-~

I.t2A~

~ " o

/ / / / ~ , 7 3 0 ~ ~ O O ~ C

,," ; . ~ . ~

/ : . / o; \

' / i\ ! :

. . . . . . . . . I . . . . . . . . . I ' ' ~ . . . . . ~*1 . . . . . . . . . I . . . . . . . . . I . . . . . . . . . I . . . . . . . . . I . . . . . . . . i . . . . . . . . . L . . . . . . . . . 10 2 0 3 0 4-0 5 0 6 0 7 0 8 0 9 0 100

A t o m i c P e r c e n t I r o n Fe

5 0 0 0

Co

T. Nishizawa and K. Ishida, 1984.

Fig. 2 Solid/Liquid and 8/1, Equilibrium in the Co-Fe System

0 1 6 0 0

1 5 5 0

L~ 0

1 4 5 0

1 5 0 0 ~

1 4 0 0

1 3 5 0 - I . . . . . . . . . , , ,

W e i g h t P e r c e n t I r o n 10 20 30 40 50 60 70 80 90 100

. . . . . I . . . . i i . . . . . I . . . . i [ . . . . . I . . . . i L . . . . . I , , , i . . . . . . . . . i

F , d

. . . . . . . . . i . . . . . . . . . i 0 20 4 0 6 0 80 100

Co A t o m i c P e r c e n t I r o n Fe

T. Nishizawa and K. Ishida, 1984.

B u l l e t i n o f A l l o y P h a s e D i a g r a m s V o l . 5 N o . 3 1 9 8 4 2 5 1

Co-Fe Provisional

Fig. 3 a / , y Equilibrium and Curie Temperature in the Co-Fe System

C

k

0 tO

mNiis|mllm

ltO0 ~ ,

900

700

500

Co

\ "~x.

W e i g h t P e r c e n t I r o n 20 30 40 50 60 70 80 9O tOO

7 ~

NI~ o [ []

/ I / A

/ /

[ ] / t r l ]

�9 / i , /

J

/ , i l d ~

i ! l i

i

I I i i

I : i i

2O

L / \ : �9 \

/ \ 40 60 80 iO0

A t o m i c P e r c e n t I r o n Fe

T. Nishizawa and K. Ishida, 1984.

measurements [41Ell, 70Fisl, 75Nor]. The a / ' y phase boundary is well established at >30% Fe, which reaches a maximum of 985 ~ at about 55 at.% Fe, and the (a + ~) two-phase field is very narrow. In the region Fe < 30%, the (a + ~) phase field becomes wider, a l though the narrowing of the two-phase field was proposed [78Mas].

Effect of Co on a(bcc) -* s(cph) transformation of Fe at room temperature has been studied under high pressure [66Lor, 71Bun, 77Pap]. The transformation pressure in- creases with addition of Co in Fe in the region between 0 and 50 wt.% Co content.

Order-Disorder Transformation. The equiatomic alloy of Fe and Co undergoes the order-disorder transformation at 730 ~ and the ordered phase a ' exists over a considerable range on either side of the stoichiometric composition (Fig. 1). The composition dependence of the order-disorder transformation temperature of FeCo was established by specific heat measurements [67Asa, 71Cas, 74Ore, 75Nor], neutron diffraction [77Oye], and thermal analysis [70Yoo, 77Oye], as shown in Fig. 4. The critical temperature, To, of equiatomic composition was found to be 736 ~ [67Asa], 726 ~ [70Yoo, 81Ros], 729.5 ~ [71Cas], 722 ~ [74Ore], 728 ~ [81But], and 723 ~ [77Oye]. The theoretical calcu- lations of order-disorder t ransi t ion are presented by [77Ind]. The transformation temperature, To, is raised by increasing pressure [70Yoo], although some conflicting data were recently obtained [81But].

Ordering kinetics was investigated by [66Dor, 73Cle, 74Eym, 74Kom, 75Tak, 76Gro, 76Hag, 76Sat, 77Mal, 78Eym, 79Buc, 79Kud2, 80Der, 80Mor, 80Rac, 81All].

Although the existence of superlattices based on the com- positions Fe3Co and FeCo3 was suggested [54Mas, 57Vit,

63Gol], direct evidence of the superstructure was not given. The studies of neutron diffraction [67Asa] and calo- rimetric measurement [70Vel] indicated evidence against the existence of the superlattices. The 550 ~ anomaly in FeCo, which has been observed as breaks of electrical re- sistence, specific heat, hardness, magnetic properties, and thermoelectromotive force, has not been fully explained. [71Yok], however, concluded that the 550 ~ anomaly does not exist in equilibrium.

Magnetic Transformation. The measured Curie tem- pera ture , according to recent invest igat ions [69Stu, 75Nor], is shown in Fig. 3. The data are in good agreement with the previous results quoted by [Hansen]. According to [75Nor], however, a coincidence of the magnetic and a/, / transformations occurs at about 31 at.% Fe and 78 at.% Fe for the Co-rich and Fe-rich side, in contradiction to the previous findings at about 26 at.% Fe and 85 at.% Fe, respectively�9

Metastable Phases Martensitic Transformation on the Fe-Rich Side. The su- percoo l ing of aus ten i te on the Fe-rich side was in- vestigated extensively [67Det, 67Par, 70Gri, 70hu, 79Mir, 81Mir], and it was well es tabl ished tha t the t rans- formation temperature depends on the cooling rate [67Par, 70Izu, 81Mir]. Figure 5 shows the effect of Co on the trans- formation temperature, which has been drawn from the four constant temperature plateaus (I-IV) in the graph of t r ans fo rmat ion t e m p e r a t u r e vs cooling rate. The t ransformat ion t empera tu re changes from stage I to stage IV with increasing cooling rate; i.e., curve I-IV at cooling rates of about 103 - 5 x 104, 5 • 104 - 8 • 104 , 8 x 104 - 105, and more than l0 s ~ respectively. The

252 Bulletin ofAlloy Phase Diagrams Vol. 5 No. 3 1984

Fig. 4

8 0 0

Order-Disorder Transformation Temperature of FeCo

W e i g h t P e r c e n t I r o n

10 20 30 40 50 60 70 80 90 100 . . . . . i . . . . . . . . . J . . . . I I . . . . . i . . . . I l . . . . . i . . . . i i . . . . . L . . . .

o

7 0 0 �9

L) o

600 -

500-

400 ' ,

Co

Provisional Co-Fe

20 0 60 80 100 A t o m i c P e r c e n t I r o n F e

T. Nishizawa and K. Ishida, 1984.

Fig. 5 Martensitic Transformation Temperature in Fe-Co Alloys

1000

800 o

soo- E

p -

400 40

I O O

/ /o f l-r[ O

A Parr

o I z u m i y a m a

�9 M i r a e v et

0 I

u

0 ~ e . _ _ . _

O - o

0 ~ Z ~ ~ 0 ~ 0 0 . 0 ~ 0 . '

~ o et aL. "e \~ al. �9 ~

�9 -_... 1T,,,' e \

O \ 0 \ 0

%

I I �9

60 80 100

wt.% Fe

T. Nishizawa and K. Ishida, 1984.

stage kinetics of this transformation can be attributed to several different processes of interaction between the in- terface and impurities [81Mir]. The maximum supercooled temperature of austenite rises up to about 40% Co and then decreases.

Fig. 6 Martensitic Transformation Temperature in Co-Fe Alloys

5001

7 o Krajewski et O L

oC ) M s u r n o t o & Wotanabe

200 ~ ~- ~ ~ As

100

Ms 0 1 I I I I

0 1 2 3 4 5

wt.% Fe

T. Nishizawa and K, Ishida, 1984.

Martensitic Transformation in the Co-Rich Side. The ~,/E transformation temperature of Co is markedly decreased by the addition of Fe [70Kra, 73Has, 78Mas]. Figure 6 shows the martensi te s tar t and reverse temperatures [70Kra, 78Mas]. Internal friction [75Bou] and crystallo- graphic characteristics [77Mahl, 77Mah2, 78Mah] accom- panied by martensitic transformation were reported.

Bulletin ofAlloy Phase Diagrams Vol. 5 No. 3 1984 253

Co-Fe Provisional

Fig. 7 Transformation Diagram of Co-Fe Alloys

5001 0 r ~ 0

400

0 o �9 A O �9 v \

300~ �9 ,

o 200 I ~ E

i00I-

0 0 Co

�9 0.0

\ 77 ,

\

x

I x

�9 E o77 ~ 7

7

l 1 I I I I I

2 3 4 5 6 7 8 9

mt?lo Fe

T. Nishizawa and K. Ishida, 1984.

Table I Co-Fe Crystal Structure Data

Approximate composition(a), Pearson Space

Phase at.% Fe symbol group Prototype

e orCeCo) . . . . . . . . 0to 6 hP2 P63/mmc Mg T . . . . . . . . . . . . . . . 0 to 100 cF4 Fm3m Cu a'. . . . . . . . . . . . . . . 25to 75 cP2 Pm3m CsC1 a or (aFe) . . . . . . . 25 to 100 cI2 Im3m W 8 . . . . . . . . . . . . . . . . 83 to 100 cI2 Im3m W

M e t a s t a b l e p h a s e

+7 . . . . . . . . . . . . . . . 0.5 to 6 hP4 P6Jmmc La

(a) According to the phase diagram.

Table 2 Lattice Parameters of the a Phase of Co-Fe Alloys

Lattice parameter, nm Composit ion, Quenched Quenched from

at.% Co from 750 ~ 600 ~ Slow cooled

0 . . . . . . . . . . . . . . . . 0.28860 . . . . . . 8 . . . . . . . . . . . . . . . . 0.28668 . . . . . .

15 . . . . . . . . . . . . . . . . 0.28669 . . . . . . 21 . . . . . . . . . . . . . . . . 0.28666 "" 0.28666 23 . . . . . . . . . . . . . . . . 0.28664 "'" 0.28662 25 . . . . . . . . . . . . . . . . 0.28658 "" 0.28656 27 . . . . . . . . . . . . . . . . 0.28652 ... 0.28648 30 . . . . . . . . . . . . . . . . 0.28642 "" 0.28633 32.5 . . . . . . . . . . . . . . . 0.28633 "'" 0.28621 35 . . . . . . . . . . . . . . . . 0.28623 0.28618 0.28611 37.5 . . . . . . . . . . . . . . . 0.28610 "'" 0.28605 40 . . . . . . . . . . . . . . . . 0.28597 0.28597 0.28597 42.5 . . . . . . . . . . . . . . . 0.28587 0.28591 0.28594 45 . . . . . . . . . . . . . . . . 0.28576 0.28581 0.28588 48 . . . . . . . . . . . . . . . . 0.28563 0.28569 0.28578 50 . . . . . . . . . . . . . . . . 0.28543 0.28553 0.28563 52.5 . . . . . . . . . . . . . . . 0.28525 0.28531 0.28541 55 . . . . . . . . . . . . . . . . 0.28512 0.28519 0.28522 60 . . . . . . . . . . . . . . . . 0.28486 0.28488 0.28490 67.5 . . . . . . . . . . . . . . . 0.28445 ... 0.28445 70 . . . . . . . . . . . . . . . . 0.28422 ... 0.28422 72.5 . . . . . . . . . . . . . . . 0.28410 "" 0.28410

Fig. 8 Change in Crystal Structure of Co-Fe Films During Heating

7 (fcc)

o +o0- \ / /

"~ 400~ ~/ ', 2 ~ T e e \\\ e(bcc)

E 200- r ~x + E

(cph x x

0 Co 10 20 30

a t. % Fe T. Nishizawa and K. Ishida, 1984.

Metastable Phases. It has been found tha t a metas table +7 phase wi th a double cph s t ruc ture is formed in Co- rich alloys. The +7 phase was first detected by [71Woo] in the su r f ace l a y e r o f Co-(2 to 5)% Fe a l loys as a result of cavitation-erosion. [72Ono, 74Ono], using high- t empera tu re X-ray diffraction and h e a t capacity mea- surements , showed tha t this phase is also formed during isothermal soaking or slow cooling in the range 1.5 to 4.8 at.% Fe, as shown in Fig. 7. [76Nik1, 76Nik2, 77Nik] pointed out t h a t the +7 phase also appears mar tens i t ica l ly with surface re l ief and t ransforms to cph phase by defor- mation, so tha t the T/phase cannot be an equi l ibr ium but ra ther is a metas table phase.

The polymorphic t ransformat ion and physical properties of thin films were reviewed by [77Bur]. F igure 8 shows the phase changes in Co-Fe thin films. The order-disorder t ransformat ion in Fe-Co thin films was studied by electron diffract ion and nuc lea r magne t i c resonance [79Kudl , 79Kud2], and MSssbauer spectroscopy [78Bay]. The phase s t a b i l i t y of Co-Fe w h i s k e r s [74Ki t , 78Bon, 79Bon l , 79Bon2], epi taxia l crystals [69Pyn, 75Rep, 79Bes], and electrodeposi ted phases [71Vit, 73Kov, 75Pov, 76Mue, 76Pov, 78Pov] has been discussed.

Crystal Structures and Lattice Parameters

The crys ta l s t r u c t u r e of e q u i l i b r i u m and m e t a s t a b l e phases are summarized in Table 1. The latt ice parameters were measu red in a [41Ell, 67Asa, 69Stu, 73Zwe], a ' [41Ell, 67Asa, 78Tah], T [41Ell, 74Ono], ~ [74Ono], and 7/ [74Ono] phases. The effect of order ing on the latt ice pa- rameter makes an increase in cell size in the 40 to 60 at.% Co alloys and a decrease in the 23 to 30 at.% Co alloys, as shown in Table 2 [67Asa]. [69Stu] invest igated the re la t ionship between lat t ice p a r a m e t e r and tempera- ture. Co addit ions progressively reduced the magni tude of the lat t ice pa rame te r anomaly near Cur ie t empera tu re until 12 wt.% Co. Figure 9 shows the lat t ice spacings of T, e, and 77 phases [74Ono].

254 Bul le t in of Alloy Phase Diagrams Vol. 5 No. 3 1984

Provisional Co-Fe

Thermodynamics

Liquid P h a s e . The activities in liquid metal l ic solution were studied by the K n u d s e n cell mass spect rometry [67Bel, 77Sir, 81Ram] and t ranspi ra t ion method [78Marl. [67Bell reported positive deviations of both Fe and Co from ideality, whereas negat ive deviations have been general ly observed [77Sir, 78Mar, 81Ram]. The calorimetric studies of the heats of mixing indicated negative values [70Pre, 73Toz, 74Bat, 81Igu].

So l id P h a s e . Thermodynamic properties such as the en- thalpies of formation [71Mull and activities [56Sat, 76Vre, 81Ram] of the T phase were studied. The most recent data [81Ram] indicated negat ive deviations from ideal i ty for all composition between Xco = 0.05 to 1.00 and positive devi- at ions below Xco = 0.05. The heats of t ransformat ion be- tween a and T phases were found to be 5400 to 5900 J /mol [62Ste, 71Mull. The enthalpies of formation of the dis- ordered a and ordered a ' phases were de te rmined by calorimetric studies [71Mul, 78Ars].

Thermodynamic Parameters. The Gibbs energies of the solution phases are approximated in the regular solution model as:

A G i o i ~ x = Gco(1 - x) + re

+ R T [ x l n x + (1 -x) In (1 - x)] i + ~qcoreX(1 - x) (Eq 1)

where x is the Fe atomic fraction, T is the absolute tern- perature, ~ and ~ are lattice stabil i ty te rms for the pure elements in phase i, and lZ~ore is the in teract ion pa- rameter tha t depends on temperature and composition. The phase boundary is calculated by min imiz ing the Gibbs energy of the system or, equivalently, equi l ib ra t ing the chemica l po t en t i a l of each component . The the rmo- dynamic parameters to calculate the phase d iagram are presented in Table 3 [73Kau, 78Kau]. The magnet ic con- t r ibut ions to the Gibbs energy are reviewed by [77Mio, 82Ind, 82Mio]. The calculated and assessed d iagrams are compared in Fig. 10.

Addit ional information on the thermodynamic properties of Co-Fe system is given in [68Lap, 70Fis2, 70Lan, 71Tse, 73Ind, 73Kau, 73Kov, 73Spe, 73Ust, 73Waz, 74Din, 75Bat, 75Des, 75Dyu, 75Hsu, 76Arg, 76Hsu, 78Bod, 78Pet, 79Ben, 79Ere, 79Ko, 79Ost, 80Ego].

Cited References *41Elh W.C. Ellis and E.S. Greiner, "Equilibrium Relations in

the Solid State of the Iron-Cobalt System", Trans. ASM, 29, 415 (1941). (Equi Diagram; Experimental; #)

*53Har: G.B. Harris and W. Hume-Rothery, "The Liquidus- Solidus Relations in the System Iron-Cobalt in the Range 0-30 at.% Cobalt", J. Iron Steel Inst., 174, 212 (1953). (Equi Diagram; Experimental; #)

54Mas: H. Masumoto, H. Saito, and M. Shinozaki, "On the Order- Disorder Transformation of the Alloys of Iron and Cobalt", Sci. Rep. Res. Inst. Tohoku Univ., 6, 523 (1954). Equi Diagram, Crys Structure; Experimental)

*56Sat: T. Satow, S. Kachi, and K. Iwase, "Thermodynamic Ac- tivities in Iron-Cobalt Solid Solutions", Sci. Rep. Res. Inst. Tohoku Univ., 8, 502 (1956). (Thermo; Experimental)

Fig. 9 Lat t ice P a r a m e t e r of % ~, and e P h a s e s in the C o - F e S y s t e m

E e-

(D (D

(D

. - I

8 0.'6 i o o--o-o-, ~ 0 . 1 6 I r I

I

I 0.205L ', l

o 0.2041- I 0 " ~ I coCO' I I I

,,, ,, 0.2 5 i Lc~,l J f

o ,

O 0.2501 - ' ' I I t

0 2 4

Q t . % Fe

I

I I I I

I I

I I

I I

o--O--O--- I I I t 6 8 10

T. Nishizawa and K. Ishida, 1984.

Table 3 Thermodynamic Parameters in the Co-Fe System Element Lattice stability parameters [73Kau, 78Kau], J / m o l , T i n K

C o . . . . . . . . . . . . . . . . . . . . . . . ~ -- ~176 0GcPh _ 0Glee

OGliq _ OGfCC

Fe . . . . . . . . . . . . . . . . . . . . . . . ~ - ~162162

oGcPh _ OG~Or oG.q _ OGfec

6953 - 0.63137 • 10-2T 2 + 2.8037 x 10-6T 3 -460.24 + 0.6276 T

16192.08 - 9.16296T -5235 + 9.4T - 0.5295 • 10-2T 2 + 0.9221 • 10-6T 3

-6108 + 3.4618T + 0.7472 • 10 2T2 - 0.51254 • 10 ~T 3 - 1828.408 + 4.6861 T 14 744.416 - 8.368 T

(1100 < T < 1800) (300 < T < 1100)

Phase Interaction parameters [73Kau, 78Kau], J/mol, T in K

fcc . . . . . . . . . . . . . . . (-2322 + 2.0849 • 10-3T 2 - 0.42931 x 1 0 - 6 T 3 ) X F e + (-983 + 0.57337 x 10 2T2 - 1.1811 x 10-6T3)xco bcc . . . . . . . . . . . . . . . (-36945 + 0.50036 • 1G 1T2 - 2.1701 • 10 5T3)XFe + (--39886 - 0.43706 • 10-1T 2 - 1.6563 x 10-ST2)xco cph . . . . . . . . . . . . . . (1433 + 2.0849 • 10-3T 2 - 0.42941 • 1O-6T3)XFe + (2782 + 0.57337 • 10-2T 2 - 1.1811 • 10-6T3)xco liq . . . . . . . . . . . . . . . (-6904 + 4.60T)XFe + (--12803 + 12.38T)xco

Bullet in ofAlloy Phase Diagrams Vol. 5 No. 3 1984 255

Co-Fe Provisional

Fig. 10 Comparison of Assessed and Calculated Diagrams in the Co-Fe System Weight Percent Iron

0 10 ~0 30 40 5(3 ~0 70 flO 9(} 100 tTO0 ] . . . . ' . . . . i . . . . . ; . . . . , I . . . . .~ , . . . . ~ ~ . . ~ . ~ _

" ~ IIINI SgmlllWl

L

1394~ p

_, 13oo~ ~y

P. 4

900

/ s 4 / {

500 ~ . . . . . . . . . I r , I

0 20 40 60

Co Atomic Percent I ron 80 i00

Fe

T. Nishizawa and K. Ishida, 1984.

57Vit: L. M. Viting, Zh. Neorg. Khim., 2. 845 ~1957). ~Crys Struc- ture; Experimental)

*62Ste: W. Steiner and O. Krisement, "Bildungsw~rmen von a und ), Eisen-Kobalt Legierungen", Arch. Eisenhitttenwes., 33, 877 (1962)./Thermo: Experimental)

63Goh A. A. Goldenberg and Y. P. Selissky, Fiz. Met. Metalloved., 15, 717 t1963}. (Crys Structure; Experimental)

66Dor: Y.A. Dorofeev, B.G. Lyashchenko, and L.I. Novak, "Neutron Diffraction Analysis of Fe-Co Atomic Ferromagnetic

Superlattices", Izv. Akad. Nauk SSSR Ser. Fiz., 30, 964 (1966). (Crys Structure; Experimental)

*66Lor: T. R. Loree, C. M. Fowler, E. G. Zukas, and F. S. Minshall, "Dynamic Polymorphism of Some Binary Iron Alloys", J. Appl. Phys., 37, 1918 (1966). (Pressure; Experimental)

*67Asa: H. Asano, Y. Bando, N. Nakanishi, and S. Kachi, "Order-Disorder Transformation of Fe-Co Alloys in Fine Particles", Trans. Jpn. Inst. Met., 8, 180 (1967). (Equi Diagram, Crys Structure; Experimental; #}

67Beh G.R. Belton and R. Fruehan, "Determination of Activi- ties by Mass Spectrometry, I. The Liquid Metallic Systems Iron-Nickel and Iron-Cobalt", J. Phys. Chem., 71, 1403 (1967). (Thermo; Experimental)

67Dep: J. R. Depew and D.E. Speliotis, "Magnetic Properties of Chemically Deposited Cobalt-Iron Films", Plating, 54, 705 (1967). (Meta Phases, Crys Structure; Experimental)

67Det: K. Detert, "Investigation for Raising the Alpha to Gamma Transformation Temperature in Iron-Cobalt Alloys", High- Temperature Magnetic Materials, NASA, 123 (1967). (Meta Phases; Experimental)

*67Par: J.G. Parr, "Transformations in Fe-Co Alloys", J. Iron Steel Inst., 205, 426 (1967). (Meta Phases; Experimental)

68Lap: D.M. Laptev, "Use of the Heat of Melting in Statistical Thermodynamical Calculations of the Melting Diagrams of Me- tallic Systems", Zh. Fiz. Khim., 42, 726 (1968) in Russian. (Thermo; Experimental)

69Pyn: V.G. Pynko, M.A. Ovsyannikov, S.G. Rusova, A.S. Komalov, and M.N. Rukosuev, "Phase Composition and Epi- taxial Growth of Films of Iron, Nickel, and Cobalt Alloys", Fiz. Khim. Khim. Tekhnol., Sb. Mater. Nauch. Tekh. Konf. Rab.

Nauki Proizvod, 29 (1969). (Meta Phases, Crys Structure: Experimental)

*698tu: H. Stuart and N. Ridley, "Lattice Parameters and Curie- Point Anomalies of Iron-Cobalt Alloys", Brit. J. Appl. Phys., Ser. 2,485 (1969). (Thermo; Experimental)

*70Fisl: W.A. Fisher, K. Lorenz, H. Fabritius, and D. Schlegel, "Examination of the Alpha-Gamma Transformation in Very Pure Binary Alloys of Iron with Molybdenum, Vanadium, Tungsten, Niobium, Tantalum, Zirconium, and Cobalt", Arch. Eisenhitttenwes., 41, 489 (1970). (Equi Diagram, Thermo; Experimental; #)

70Fis2: S.G. Fishman, D. Gupta, and D.S. Lieberman, "Dif- fusivity and Isotope-Effect Measurements in Equiatomic Fe-Co", Phys. Rev. B, 6, 1451 (1970). (Thermo; Experimental}

70Gri: V.N. Gridnev and S.P. Oshkaderov, "Critical Points of Iron-Cobalt Alloys on Rapid Heating", Akad. Nauk Ukrain. SSR Metallofiz., 27, 84 (1970). (Meta Phases; Experimental)

*70Izu: M. Izumiyama, M. Tsuchiya, and Y. Imai, "Effects of Al- loying Element on Supercooled A3 Transformation of Iron", Sci. Rep. Res. Inst. Tohoku Univ., Ser. A, 22, 105 (1970). (Meta Phases; Experimental)

*70Kra: W. Krajewski, J. Kruger, and H. Winterhager, "Allo- tropic Change and Thermal Expansion of Pure Cobalt, Cobalt- Chromium, and Cobalt-Iron Alloys", Metall., 24, 480 (1970). (Meta Phases; Experimental)

70Lan: K.W. Lange, "General Observations and Correlations for the Activities in Binary Iron, Cobalt, and Nickel Alloys", Arch. Eisenhiittenwes., 41, 125 (1970). (Thermo; Theory)

*70Pre: B. Predel and R. Mohs, "Thermodynamic Investigations of the Iron-Nickel and Iron-Cobalt Systems", Arch. Eisen- hiittenwes., 41, 143 (1970). (Equi Diagram, Thermo; Experi- mental; #)

70Veh J. Velisek, "Ordering Processes in Iron-Cobalt Alloys Stud- ied by Heat-Temperature Spectra", Czech. J. Phys., B20, 250 (1970}. (Crys Structure, Thermo; Experimental)

*70Yoo: D. N. Yoon and R. N. Jeffery, "Pressure and Composition Dependence of the Order-Disorder Critical Temperature of a-CoFe", J. Phys. Chem. Solids, 31, 2635 (1970). (Pressure; Experimental)

256 Bul le t in o fAl loy Phase Diagrams Vol. 5 No. 3 1984

Provisional Co-Fe

71Bun: F. P. Bundy, "Resistance-Jump Phase Changes Useful for High-Pressure Calibration", NBS Spec. Publ., No. 326, 263 ( 1971). (Pressure; Experimental)

*71Cas: R. Castanet and A. Ferrier, "Heat Capacity and Thermo- dynamic Functions of the Equimolecular Iron-Cobalt Alloy", Compt. Rend., 272C, 15 (1971). (Thermo; Experimental)

*71Mul: F. Miiller and F. H. Hayes, "Thermodynamic Properties of Iron Plus Cobalt Alloys, Part 1, Calorimetric Study of the Solid Alloys", J. Chem. Thermodyn., 3, 599 (1971). (Thermo; Experimental)

71Tse: L.S. Tsemekhman, S~E. Vaisburd, and Z.F. Shirokova, "Activities of Components in Iron-Nickel, Iron-Cobalt, and Nickel-Cobalt Binary Metals, Zh. Fiz. Khim., 45, 2074 (1971). (Thermo; Experimental)

71Vit: S. Vitkova and N. Pangarov, "Structure and Orientation of Electrolytically Deposited Beta Cobalt and Cobalt-Iron Alloys, Izv. Otd. Khim. Nauki Bulg. A kad. Nauk, 44, 681 (1971). (Meta Phases, Crys Structure; Experimental)

*71Woo: D. A. Woodford and H. J. Beattie, "Deformation-Induced Phase Transformation Involving a Four-Layer Stacking Se- quence in a Co-Fe Alloy", Met. Trans., 2, 3223 (1971). (Meta Phases, Crys Structure; Experimental)

*71Yok: T. Yokoyama, T. Takezawa, and Y. Higashida, "550 ~ Change of FeCo Superlattice Alloy", Trans. Jpn. Inst. Met., 12, 30 (1971). (Equi Diagram, Crys Structure; Experimental)

72Ono: T. Onozuka, S. Yamaguchi, M. Hirabayashi, and T. Wakiyama, "Double cph Structure in Cobalt Alloys with Di- lute Content of Iron", J. Phys. Soe. Jpn., 33, 857 (1972). (Meta Phases, Crys Structure; Experimental)

73Cle: D.W. Clegg and R.A. Buckley, "Disorder to Order Trans- formation in Fe-Co Based Alloys", Met. Sci. J., 7, 48 (1973). (Crys Structure; Experimental)

73Dek: M. V. Dekhtyar, "Effect of the Irreversible Process in the Transformation of the Metastable Disordered Alpha Phase on the Magnetic Properties of an Fe-Co Alloy", Fiz. Met. Metal- loved., 36, 711 (1973); TR: Phys. Met. Metallogr., 36(4), 31 (1973). (Meta Phases, Crys Structure; Experimental)

73Has: U. Hashimoto, "Influence of Added Elements on Allo- tropic Transformations", Trans. Nat. R es. Inst. Met. Jpn., Suppl., 15, 1 (1973). (Meta Phases; Review)

73Ind: G. Inden and W. Pitsch, ~Interchange Energies in Fe-Co Solid Solutions and Their Influence on Order-Disorder and Seg- regation Process", Proc. Int. Symp. on Chemical Metallurgy of Iron and Steel, 330 (1973). (Thermo; Theory)

*73Kaul: L. Kaufman and H. Nesor, "Calculation of the Binary Phase Diagrams of Fe, Cr, Ni, and Co", Z. Metallkd., 64, 249 (1973). (Equi Diagram, Thermo; Theory; #)

73Kau2: L. Kaufman and H. Nesor, "Theoretical Approaches to the Determination of Phase Diagrams", Annual Review of Ma- terials Science, 3, 1 (1973). (Equi Diagram, Thermo; Theory)

73Kov: V.I. Kovtun, A.G. Vinitskii, Y.V. Krivusha and A.K. Karaulov, "Mechanism of the Electrocrystallization of Cobalt- Iron Alloys", Izv. Akad. Nauk SSSR, Met., 2, 239 (1973). (Crys Structure, Meta Phases; Experimental)

73Kue: R. Kuentzler, "Low-Temperature Specific Heat of Ordered and Disordered Iron-Cobalt (Fe-Co)", Phys. Status Solidi (b), 58, 519 (1973). (Thermo; Experimental)

738pe: P.J. Spencer, F.H. Hayes, and L. Elford, "Relation Be- tween Binary and Ternary Alloy Properties, Calorimetric Investigation of the Iron-Cobalt-Nickel System", Chemical Metallurgy of Iron and Steel, The Iron and Steel Inst., 322 (1973). (Thermo; Experimental)

73Toz: Y. Tozaki, Y. Iguchi, S. Ban-ya, and T. Fuwa, "Heat of Mixing of Iron Alloys", Chemical Metallurgy of Iron and Steel, The Iron and Steel Inst., 130 (1973). (Thermo; Experimental)

73Ust: T. Ustad and H. Sorum, "Interdiffusion in the Fe-Ni, Ni-Co, and Fe-Co System", Phys. Status Solidi (a), 20, 285 (1973). (Thermo; Experimental)

73Wak: T. Wakiyama, ~'Magnetic and Crystalline Properties of Hexagonal Cobalt-Iron Alloys", AIP Conf. Proc., 10, 921 (1973). (Crys Structure; Experimental)

73Waz: A.R. Wazzan, A. Bristoti, L.B. Robinson, and A. Ahme- dieh, "Temperature Dependence of the Single-Crystal Elastic

Constants of Cobalt-Rich Cobalt-Iron Alloys, J. Appl. Phys., 44, 2018 (1973). (Crys Structure; Experimental)

73Zwe: L. Zwell, G. R. Speich, and W. C. Leslie, "Effects of Co, Cr, Ir, Pt, Re, Rh, and Ru on the Lattice Parameter and Density of Alpha Fe", Metall. Trans., 4, 1990 (1973). (Crys Structure; Experimental)

74Bat: G.I. Batalin, N.N. Minenko, and V.S. Sudartsova, "En- thalpies of Mixing and Thermodynamic Properties of Liquid Alloys of Iron with Manganese, Cobalt, and Nickel", Izv. Akad. Nauk SSSR, Met., (5), 99 (1974). (Thermo; Experimental)

74Bur: V.A. Buravikhin, V.V. Litvintsev, Y.N. Didovich, V.G. Kazakov, and A.I. Ushakov, "Magnetic and Electrical Proper- ties of Co-Rich Co-Fe Films", Czech. J. Phys., B24, 636 (1974). (Meta Phases; Experimental)

74Din: J. F. Dinhut, J. C. Desoyer, and P. Moine, "Application of the Method of Moments to the Equiatomic Alloy FeCo", J. Phys., 35, 447 (1974). (Thermo; Theory)

74Eym: J.P. Eymery, P. Grosbras, and P. Moine, "Ordering Kinetics of Various Iron-Cobalt Alloys", Phys. Status Solidi (a), 21, 517 (1974). (Crys Structure; Experimental)

74Kit: Y. Kitano, Y. Komura, T. Iwanari, and R. Kurashige, "Growth of Cobalt-Iron Alloy Whiskers", J. Cryst. Growth, 24/25, 354 (1974). (Meta Phases, Crys Structure; Experimental)

74Kom: A.S. Komalov and N.M. Repina, "Electron-Diffraction Study of Atomic Ordering in Alloys of Metals with Similar Atomic Scattering Factors", Fiz. Met. MetaUoved., 37, 877 (1974). (Crys Structure; Experimental)

'74Ono: T. Onozuka, S. Yamaguchi, M. Hirabayashi, and T. Wakiyama, "Double cph phase in Co Alloys with Dilute Con- tents of Fe", J. Phys. Soc. Jpn., 37, 687 (1974). (Meta Phases, Crys Structure; Experimental)

*74Ore: J. Orehotski and K. Schr(ider, "Order-Disorder Criti- cal Phenomena in FeCo", J. Phys. F, 4, 196 (1974). (Thermo; Experimental)

75Bat: G.I. Batallin, N.N. Minenko, and V.S. Sudavtsova, "Enthalpies of Mixing and Thermodynamic Properties of Liq- uid Alloys of Iron with Cobalt and Nickel", V. Sb. Termodinam. Svoistva Metal. Splavov, 275 (1975). (Thermo; Experimental)

75Bou: G. Bouquet and B. Dubois, "Internal Friction in Co and Co-Fe Alloy-- Interaction Between Recrystallization and Phase Transformation", 5th Int. Conf. on Internal Friction and Ultra- sonic Attenuation in Crystalline Solids, 1, 410 (1975). (Meta Phases; Experimental)

75Bur: V.A. Buravikhin, I.V. Chernykh, V.V. Litvintsev, and V.N. Pelageikin, "Thermo-Magnetic Effects in Co-Fe Films", Izv. V.U.Z. Fiz., 11 (1975). (Meta Phases; Experimental)

75Des: J.C. Desoyer, J.F. Dinhut, and P. Moine, "Energies of Different Types of Antiphase Boundaries in the Iron-Cobalt Alloy", Phys. Status Solidi (a), 31,647 (1975). (Thermo; Theory)

75Dyu: V.G. Dyubanov, A.Y. Stomakhin, and A.F. Filippov, "Enthalpies of Formation of Iron-, Cobalt-, and Nickel-Based Dilute Solutions", Izv. V.U.Z., Chernaya Metall., 5 (1975). (Thermo; Experimental)

75Hsu: Y. Hsu and L. Berger, "Magnon Heat Conduction and Magnon Lifetimes in the Metallic Ferromagnet Iron-Cobalt (Fe6sCo32) at Low Temperatures", AIP Conf. Proc., 24, 176 (1975). (Thermo; Experimental)

75Kru: D. Krueger, L.S. Pa la tn ik , and A.I . Fedorenko, "Correlation Between Crystal and Domain Structures of Thin Iron-Cobalt Films", Fiz. Met. Metalloved., 39, 757 (1975). (Meta Phases, Crys Structure; Experimental)

*75Nor: A.S. Normanton, P.E. Bloomfield, F.R. Sale, and B.B. Argent, "A Calorimetric Study of Iron-Cobalt Alloys", Met. Sci., 9, 510 (1975). (Equi Diagram, Thermo; Experimental; #)

75Pov: V.V. Povetkin, A.I. Zhikharev, and M.S. Zakharov, "Preferential Orientation of Crystallites of an Electrodeposited Cobalt-Iron Alloy", Tr. Tyumen. Ind. Inst., 32, 121 (1975). (Meta Phases, Crys Structure; Experimental)

75Rep: N.M. Repina, '~Aging of Iron-Cobalt Alloys in Thin Epitaxial Single Crystals", V. Sb. Plenoch. MonokristaUy Magnit. Ushchikhsya Veshchestv, 44 (1975). (Meta Phases; Experimental)

75Tak: T. Takazawa and T. Yokoyama, "Change in Volume in

Bul le t in ofAl loy Phase Diagrams Vol. 5 No. 3 1984 257

Co..Fe Provisional

Ordering of Fe-Co Superlattice Alloys, J. Jpn. Inst. Met., 39, 863 (1975). (Crys Structure; Experimental)

76Arg: B. B. Argent, "Calculation of Ms for Fe-Co and Fe-Cr Al- loys, Met. Sci., 10, 409 (1976). (Meta Phases, Thermo; Theory)

76Gro: P. Grosbras, J. P. Eymery, and P. Moine, "Characteristics of the D i s o r d e r to O r d e r T r a n s f o r m a t i o n in Fe-Co Alloys-- Effect of V Additions", Acta Met., 24, 189 (1976). (Crys Structure; Experimental)

76Hag: M. Hagiwara and T. Suzuki, "Effect of the Addition of a Third Element (Cr, Mn or V) on the Order-Disorder Transition Temperature in Fe-Co", J. Jpn. Inst. Met., 40, 738 (1976). (Thermo, Crys Structure; Experimental)

76Hsu: Y. Hsu and L. Berger, "Magnon Heat Conduction and Magnon Lifetimes in the Metallic Ferromagnet Iron-Cobalt (Fe~Co32) at Low Temperatures", Phys. Rev. B, 14, 4059 (1976). (Thermo; Experimental)

76Mue: E. Muenster and J. Richter-Mendau, "Electron Micro- scopic Investigations of Thin CoToFe3o Films Deposited at Oblique Incidence", Exp. Tech. Phys., 24, 51 (1976). (Meta Phases, Crys Structure; Experimental)

*76Nikl: B.I. Nikolin and Y.N. Makogon, "Martensitic Trans- formations in Co-Fe Alloys", Fiz. Met. Metalloved., 41, 1002 (1976) in Russian; TR: Phys. Met. Metallogr., 41(5), 88 (1976). (Meta Phases, Crys Structure; Experimental)

76Nik2: B.I. Nikolin and Y.N. Makogon, "Morphology and Cer- tain Properties of Martensitic Alpha- and Eta-Phases in Co-Fe Alloys'" Akad. Nauk Ukr. SSR Metallofiz., 66, 97 (1976). (Meta Phases, Crys Structure; Experimental)

76Pov: V.V. Povetkin, A.I. Zhikharev, and V.A. Valov, "Pre- ferred Orientation of a Cobalt-Alloyed Iron Electrodeposit", Tr. Tyumen. Indust. Inst., 55, 109 (1976). (Meta Phases, Crys Structure; Experimental)

76Sat: H. Sato and R. Kikuchi, "Kinetics of Order-Disorder Transformations in Alloys", Acta Met., 24, 797 (1976). (Thermo; Theory)

*76Vre: J. Vrestal, J. Velisek, and A. Rek, "Determination of Thermodynamic Activities of Components in the Fe-Co System at 1500 K", Kovove Mater., 14, 625 (1976). (Thermo; Experimental)

76Wak: T. Wakiyama, "Induced Magnetic Anisotropy in Double cph Co-Fe Alloys", Magn. Magn. Mater., Metallurgical Society AIME, 560 (1976). (Meta Phases, Crys Structure; Experimental)

77Bur: V.A. Buravikhin, V.V. Litvintsev, and A.I. Ushakov, "Polymorphic Transformations and Physical Properties of Thin Films", Phys. Status Solidi (a), 40, 11 (1977). (Meta Phases; Review)

*77Ind: G. Inden, "Determination of Chemical and Magnetic Interchange Energies in bcc Alloys, III. Application to Ferro- magnetic Alloys", Z. MetaUkd., 68, 529 (1977). (Thermo, Equi Diagram; Theory)

77Mahl: S. Mahajan, D. Brasen, and T. Wakiyama, "Electron Diffraction Patterns from Transformed Cobalt-Iron Alloys", MetaUography, 10, 179 (1977). (Crys Structure, Meta Phases; Experimental)

77Mah2: S. Mahajan, M.L. Green, and D. Brasen, "A Model for the fcc--* cph Transformation, Its Applications and Experi- mental Evidence, Met. Trans., 8A, 283 (1977). (Meta Phases, Crys Structure; Experimental)

77Mah E. I. Maltsev, V. I. Gomankov, I. M. Puzei, and A. D. Sko- kov, "Neutron-Diffraction Studies of Atomic Ordering Pro- cesses in Iron-Cobalt System Alloys", Fiz. Met. Metalloved., 43, 955 (1977) in Russian; TR: Phys. Met. MetaUogr., 43(5), 47 (1977). (Crys Structure; Experimental)

"77Mio: A.P. Miodownik, "The Calculation of Magnetic Con- tributions to Phase Stability", Calphad, 1,133 (1977). (Thermo, Equi Diagram; Theory)

77Nik: B.I. Nikolin and Y. Makogon, "Effect of Plastic De- formation on Phase Changes in Co-Fe Alloys", Akad. Nauk Ukr. SSR, MetaUofiz., 68, 87 (1977). (Meta Phases, Pressure; Experimental)

*77Oye: J .A. Oyedele and M.F. Collins, "Composition De- pendence of the Order-Disorder Transition in Fe-Co", Phys. Rev. B, 16, 3208 (1977). (Equi Diagram, Thermo; Experimental; #)

*77Pap: D. Papantonis and W.A. Bassett, "Isothermal Com- pression and bcc-cph Phase Transition of Iron-Cobalt Alloys up to 300 kbar at Room Temperature", J. Appl. Phys., 48, 3374 (1977). (Pressure; Experimental)

*77Sir: N. N. Sirota and M. B. Breslavmaslennikov, "Vapor Pres- sure and Thermodynamic Characteristics of Iron-Cobalt Sys- tem Melts", Vesti. Akad. Nauk BSSR, Ser. Fiz. Met. Navuk., 81 (1977). (Thermo; Experimental)

*78Ars: F. Arslan, H.B. Bell, and D.B. Downie, "Enthalpies of Formation of Ordered Iron-Cobalt Alloys", Met. Sci., 12, 198 (1978). (Thermo; Experimental)

78Bay: G. Bayreuther and B. Lang, "M6ssbauer Study of Ordered and Disordered Iron-Cobalt Films", J. Magn. Magn. Mater., 9, 11 (1978). (Meta Phases, Crys Structure; Experimental)

78Bod: N.E. Bodakin, B.A. Baum, and G.V. 2~r "Vis- cosity of Iron-Cobalt System Melts", Izv. V.U.Z., Chernaya Metall., 9 (1978). (Thermo; Experimental)

78Bon: A.V. Bondarenko, L.A. Naidena, and V.V. Naiden, "Iron-Cobalt Alloy Whiskers", Kristalliz. Svoistva Kristallov., 98 (1978). (Meta Phases, Crys Structure; Experimental)

78Eym: J. P. Eymery and P. Moine, "Atomic Order and M6ssbauer Spectrometry in the Equiatomic Fe-Co Alloys", J. Phys. Lett., 39, 23 (1978). (Crys Structure; Experimental)

*78Kau: L. Kaufman and H. Nesor, "Coupled Phase Diagrams and Thermochemical Data for Transit ion Metal Binary Systems", Part 1, Calphad, 2, 55 (1978). (Equi Diagram, Thermo; Theory; #)

78Mah: S. Mahajan, D. Brasen, and T. Wakiyama, "Trans- formation-Induced Microstructures in Cobalt-Iron Alloys", Metall. Trans. A, 9, 1817 (1978). tCrys Structure, Meta Phases; Experimental)

*78Mar: N. Maruyama and S. Ban-ya, "Measurement of Activi- ties in Liquid Iron-Nickel, Iron-Cobalt, and Nickel-Cobalt Alloys by a Transportation Method", J. Jpn. Inst. Met., 42, 992 (1978). (Thermo; Experimental)

78Mas: H. Masumoto and K. Watanabe, "Equilibrium Diagram of Co-Fe Binary Alloys", J. Jpn. Inst. Met., 42, 256 (1978). (Equi Diagram, Meta Phases; Experimental)

78Pet: M.S. Petrushevskii and N.S. Kosilov, "Density of Iron- Cobalt Melts", Tezisy Nauchn. Soobshch. Vses. Konf. Str. Svoist- yam Met. Shlakovykh Rasplavov, 3rd, 55 (1978). (Thermo; Experimental)

78Pov: V.V. Povetkin and M.S. Zakharov, "Structure of Iron- Cobalt Alloy Electrodeposits", Izv. Akad. Nauk SSSR, Metall., 6, 154 (1978). (Crys Structure, Meta Phases; Experimental)

78Tah: Y. Tahara, K. Mori, K. Oki, and T. Eguchi, "Variation of Lattice Constant in FeCo Alloys on Isothermal Annealing", J. Jpn. Inst. Met., 42, 1145 (1978). (Crys Structure, Thermo; Experimental)

78Tak: M. Takahashi and T. Kono, "Magnetic Anisotropy Induced by Magnetic and Stress Annealing in Co, Co-Ni, and Co-Fe Alloys", Jpn. J. Appl. Phys., 17, 361 (1978). (Crys Structure; Experimental)

78Wak: T. Wakiyama, "Crystalline and Magnetic Properties of Double Hexagonal Cobalt-Iron Alloys", Kotai Butsuri, 13, 733 (1978). (Crys Structure, Meta Phases; Review)

79Ben: W. Bendick and W. Pepperhoff, "Thermally Excited States in Cobalt and Cobalt Alloys", J. Phys. F, 9, 2185 /1979). (Thermo; Experimental)

79Bes: A. M. Bessmertnyy and E. S. Mushailov, "Features of the Alpha-Gamma Transformation in Epitaxial Cobalt-Iron Single Crystals", Fiz. Met. Metalloved., 47, 665 (1979) in Russian; TR: Phys Met. MetaUogr., 47(3), 186 (1979). (Meta Phases, Crys Structure; Experimental)

79Bonl: A.V. Bondarenko, V.P. Bazalei, and L.A. Naidena, "Characteristics of the Growth of Whiskers of Metals and Alloys During Electrolysis", Kristalliz. Svoistva Kristallov, 95 (1979) in Russian. (Meta Phases, Crys Structure; Experimental)

79Bon2: A.V. Bondarenko, V.V. Naiden, and L.A. Naidena, "Electrolytic Whiskers of an Iron-Cobalt Alloy", Materialy 3-i Vses. Konf. Nitevidn. KristaUy dlya Nov. Tekhn. Voronezh., 37 (1979) in Russian. (Meta Phases, Crys Structure; Experimental}

79Buc: R.A. Buckley and M. Rajkovic, "Order-Disorder Trans-

258 Bul le t in of Al loy Phase Diagrams Vol. 5 No. 3 1984

Provisional Co-Fe (continued)

Co-Fe Ni-Ta

formations, and the Metallography and Kinetics of Ordering in Iron-50% Cobalt-Base Alloys", Phase Transformations, 2, II- 31-II-40 (1979}. (Crys Structure; Experimental)

79Ere: V. N. Eremenko, G. M. Lukashenko, V. V. Berezutskii, and V.L. Pritula, "Thermodynamic Properties of Molten Alloys of Ni, Co, and Fe with Transition Metals", Termodin. Svoistva Met. Rasplavov. Mater. Vses. Soveshch. Termodin. Met. Splavov, 4th, 2, 48 (1979). (Thermo; Experimental)

79Ko: M. Ko and T. Nishizawa, "Effect of Cobalt on the Solu- bility Anomaly Due to Magnetic Transition in Alpha Iron, J. Jpn. Inst. Met., 43, 126 (1979). (Thermo, Equi Diagram; Experimental)

79Kudl: Y.V. Kudryavtsev, I.V. Lezhneko, and A.G. Lensik, "The Effect of the Order-Disorder Transformation on the Opti- cal Properties of Films of an Equiatomic Iron-Cobalt Alloy", Fiz. Met. Metalloved., 47, 747 (1979) in Russian; TR: Phys. Met. Metallogr., 47(4), 61 (1979). (Meta Phases; Experimental)

79Kud2: Y.V. Kudryavtsev, I.V. Lezhnenko, and A.G. Lesnik, "Electronic Structure of Iron-Cobalt Films with Equiatomic Composition in Ordered and Disordered State", Bookl. Int. Colloq. Magn. Films Surf., 9th, 181 (1979). (Meta Phases; Experimental)

79Mir: D.A. Mirzeav, T.N. Ponomareva, B.Y. Bylskii, and B.B. Ulyanov, "The Gamma to Alpha Transformation in Iron- Cobalt and Iron-Copper Alloys", Sb. Nauchn. Tr. Chelyabinsk. Politekh., 229, 95 (1979). (Meta Phases; Experimental)

79Ost: O.I. Ostrovskii and V.A. Grigoryan, "Thermodynamic Characteristics of Melts Based on Iron, Cobalt, and Nickel", Zh. Fiz. Khim., 53, 888 (1979). (Thermo; Experimental)

80Der: E.E. Deryugin, A.L. Lotkov, and L. L Gaidikova, "Neu- tronographic Study of Ordering in Iron-Cobalt Alloys", Izv. V.U.Z. Fiz., 23(12), 76 (1980). (Crys Structure; Experimental)

80Ego: V.E. Egorushkin, E.M. Savitskii, N.I. Fedyainova, and V.P. Fadin, "Kinetic Properties and the High-Temperature Phase Transition in Ni-Ti and Fe-Co Alloys", Dokl. Akad. Nauk SSSR, 251, 1376 (1980). (Thermo; Theory)

80Gal: D.K. Galkina, N.M. Kolachev, and N. Kurbanniyazov, "Galvanomagnetic Properties of Ferromagnetic Films of Iron- Cobalt Alloys", Izv. Akad. Nauk Turkm. SSR, Ser. Fiz.-Tekh., Khim. Geol. Nauk, 107 (1980). (Meta Phases; Experimental)

80Mor: J.L. Moran-Lopez and H. Wise, "Surface Composition of the Ordered Binary Alloy System: Fe-Co", Appl. Sur f Sci., 4, 93 (1980). (Thermo; Theory)

80Rae: Z. Racz and M.F. Collins, "Effect of Three-Body Inter-

actions on the Ordering of bcc Binary Alloys", Phys. Rev. B, 21, 229 (1980). (Thermo; Theory)

80Tak: M. Takahashi and S. Kadowaki, "Anomalous Temperature Dependence of the Magnetocrystalline Anisotropy in Dilute Cobalt-Iron Alloys", J. Phys. Soc. Jpn., 48, 1391 (1980). (Crys Structure; Experimental)

81Alh G. Allie, C. Lauroz, and P. Villemain, "LEED and AES Study of the (100) Surface of a 50-50 Iron-Cobalt Mono- crystalline Alloy", Surf. Sci., 104, 583 (1981). (Crys Structure; Experimental)

81But: A. K. Butilenko and I.Yu. Ignat'eva, "T-P-C Diagram of the Fe-Co System in the Ordering Region", Dop. Akad. Nauk Ukr. RSR A, (3), 43 (1981). (Equi Diagram, Pressure; Experimental)

*81Igu: Y. Iguchi, Y. Tozaki, M. Kakizaki, T. Fuwa, and S. Ban-ya, "A Calorimetric Study of Heats of Mixing of Liquid Iron Alloys", J. Iron Steel Inst. Jpn., 67, 925 (1981). (Thermo; Experimental)

*81Mir: D. A. Mirzaev, M. M. Shteinberg, T. N. Pomomareva, B. Y. Bylskii, and S.E. Karzunov, "Gamma-Alpha Phase Trans- formation in Binary Alloys of Iron with Copper, Cobalt, Ruthe- nium, and Platinum", Fiz. Met. Metalloved., 51, 364 (1981) in Russian; TR: Phys. Met. Metallogr., 51 (2), 116 (1981). (Meta Phases, Thermo; Experimental)

*81Ram: W. Rammensee and D.G. Fraser, "Activities in Solid and Liquid Iron-Nickel and Iron-Cobalt Alloys Determined by Knudsen Cell Mass Spectrometry Transportation Method", Ber. Bunsenges. Phys., 85, 588 (1981). (Thermo; Experimental)

81Riv: V. G. Rivlin, "Phase Equilibria in Iron Ternary Alloys, VI. Critical Evaluation of Constitution of Cobalt-Chromium-Iron and Cobalt-Iron-Nickel Systems", Int. Met. Rev., 26, 269 (1981). (Equi Diagram; Review)

*81Ros: P.L. Rossiter, "Order-Disorder and the Electrical Re- sistivity of Iron-Cobalt Alloy", J. Phys. F, 11, 615 (1981). (Crys Structure; Experimental)

82Ind: G. Inden, "The Effect of Continuous Transformations on Phase Diagrams", Bull. Alloy Phase Diagrams, 2, 412 (1982). (Equi Diagram, Thermo; Review)

82Mio: A. P. Miodownik, "The Effect of Magnetic Transformations on Phase Diagrams", Bull. Alloy Phase Diagrams, 2, 406 (1982). (Equi Diagram, Thermo; Review)

*Indicates key paper. #Indicates presence of a phase diagram.

Co-Fe evaluation contributed by T. Nishizawa and K. Ishida, Departments of Metallurgy, Materials Science, and Metal Processing, Tohoku University, Sendai 980, Japan. Literature searched through 1982. Professor Nishizawa is Category Editor for binary cobalt alloys.

The Ni-Ta (Nickel-Tantalum) System 58.69 180.9479

By A. Nash and P. Nash Illinois Institute of Technology

Equilibrium Diagram General Features. The equi l ib r ium phase d i ag ram of the Ni-Ta system, shown in Fig. 1, is fa i r ly well es tab l i shed and consists of five compounds (NisTa, Ni3Ta, Ni2Ta, NiTa, and NiTa2) and the t e r m i n a l solid solutions, (Ni) and (Ta). Apa r t from NisTa, there is full agreement on the react ions tha t produce all the o ther compounds.

NisTa, discovered by [70Lar2, 72Lar], was thought to form from an order ing react ion below 570 ~ in a N i - l l . 1 at.% Ta alloy. [77Pim], however, repor ted the existence of NisTa

at i000 and 1250 ~ [83Nas] confirmed the existence of this phase at h igh t empera tu re and de te rmined the peri- tectoid t e m p e r a t u r e for the format ion of NisTa to be be- tween 1320 and 1340 ~

[33The] found t ha t the compound Ni3Ta formed congru- ent ly at 1550 ~ The equi l ibr ium Ni3Ta s t ructure was first recognized by [67Gie].

The compounds Ni2Ta, NiTa, and NiTa2 were al l shown to form per i tec t ica l ly by [62Kor]. There are also two eutectic r e a c t i o n s in t h e N i - T a s y s t e m , one a t 17.2 a t .% Ta

Bul le t in of Alloy Phase Diagrams Vol. 5 No. 3 1984 259