Cobalt phase diagram

Fig. 3.8. Backscattered electron image of the transition zone between cobalt and silicon after annealing at 800°C for 230400 s (64 h) in vacuum.264 The microstructure reveals all the phases available on the equilibrium phase diagram of the Co-Si binary system. A continuous crack is seen between Co and C02SL Photograph kindly provided by Dr. A.A. Kodentsov. Reprinted with permission from Elsevier Science.

The success of this class of experiment has led to much interest in novel types of magnetic semiconductor, and the most interesting recent discovery in this domain is that zinc oxide is such a candidate when doped with small percentages of such metals as cobalt, iron and manganese. It displays a rich phase diagram whose details have yet to be fully explored and its very major attraction is the ease with which it may be made in thin film form and this procedure integrated into device fabrication routines. 

Alloys are prepared commercially and in the laboratory by melting the active metal and aluminum in a crucible and quenching the resultant melt which is then crushed and screened to the particle size range required for a particular application. The alloy composition is very important as different phases leach quite differently leading to markedly different porosities and crystallite sizes of the active metal. Mondolfo [14] provides an excellent compilation of the binary and ternary phase diagrams for aluminum alloys including those used for the preparation of skeletal metal catalysts. Alloys of a number of compositions are available commercially for activation in the laboratory or plant. They include alloys of aluminum with nickel, copper, cobalt, chromium-nickel, molybdenum-nickel, cobalt-nickel, and iron-nickel. 

The solid compounds Coi tSe(cr), CoSc2(cr), and Co9Ses(cr) have been reported to form in the system cobalt-selenium. The phase diagram of the system is presented in [72KOM/WES]. 

Figure 12.4-2 Solid-liquid phase diagram for the cobalt-copper system. The melting point of copper is 1356.6 K, and the melting point of cobalt is 1768 K.

Figure 12.4-2 is an example of the liquid-solid phase diagram for the copper-cobalt system. There we see that copper and cobalt are partially miscible in the solid phase, and that there is a region of temperature and composition in which solid cobalt is in equilibrium with molten copper-cobalt solutions. Above its melting point, cobalt is completely miscible with copper. 

Alloy of samarium with cobalt (or with Co and Fe) are technologically the most important. Figure 3 shows the Co-rich portion of the Sm-Co equilibrium phase diagram, basically after den Broeder and Buschow (1972) and Perry (1977), but with a modification of the liquidus line (shown dashed) according to Ray (1986b), who... 

Rag] Raghavan, V., Co-Fe-Si (Cobalt-Iron-Silicon) , J. Phase Equilib., 15(5), 527-528 (1994) (Phase Diagram, Review, 7)... 

Bae] Baer, G., Thomas, H., Properties and Strueture of the Iron-Cobalt Alloys with 50% Co and small Vanadium Content (in German), Z. Metallkd., 45(11), 651-655 (1954) (Electr. Prop., Experimental, Morphology, Phase Diagram, Phase Relations, 11)... 

Koe2] Koester, W., Schmid, H., Iron-Cobalt-Vanadium Ternary System. Part II (in German), Arch. Eisenhuettenwes., 26(7), 421-425 (1955) (Phase Diagram, ExperimentaL Phase Relations,, , 7)... 

Ray] Raynor, G.V., Rivlin, V.G., Phase Equilibria in Iron Ternary Alloys. 10. Critical Evaluation of Constitution of Cobalt-Iron-Vanadium System , Int. Met. Rev., 28(4), 211-227 (1983) (Phase Diagram, Phase Relations, Review, 29)... 

Syk] Sykes, W.P., Stractural and Hardening Characteristics of Some Iron-Cobalt-Tungsten Alloys , Trans. Am. Soc. Met., 25, 953-1012 (1937) (Phase Diagram, Phase Relations, Experimental, Meehan. Prop., Phys. Prop.,, 16)... 

Che] Cherkasov, P.A., Averin, V.V., Samarin, A.M., Activities of Silicon and Titanium in Molten Iron, Cobalt, and Nickel Containing Chromium , Russ. J Phys. Chem. (Engl. Transl), 42(3), 401-404 (1968), translated from Zh. Fiz. Khim, 42(3), 767 (1968) (Experimental, Phase Diagram, Phase Relations, Thermodyn., 19)... 

Sve] Sveehnikov, V.N., Markiv, V.Ya., Pet kov, V.V., Interaetion of the Intermetallide ZrCr2 with Certain Compounds of Zirconium with Iron, Cobalt and Nickel (in Russian), Akad. Nauk Ukr. SSR, Metallofizika, 42, 112-117 (1972) (Crys. Stracture, Experimental, Phase Diagram, 10)... 

Mad] Maddocks, W.R., Claussen, G.E., Section VIII - Alloys of Iron-Copper-Carbon-Cobalt , Iron Steel Inst., Special Rep., 14, 97-124 (1936) (Phase Diagram, Phase Relations, Morphology, Experimental, 12)... 

Wad] Wada, T., Wada, H., Elliott, J.F., Chipmann, J., Thermodynamies of the FCC Fe-Mn-C and Fe-Si-C Alloys , Metall Trans., 3, 1657-1662 (1972) (Thermodyn., Experimental, 12) [1972Wil] Williams, R., Bordsworth, C., Effeet of Cobalt, Copper and Manganese on the Thermodynamic Activity of Carbon in Iron-base Austenites , J. Iron Steel Inst., London, 210, 106-110 (1972) (Experimental, Phase Diagram, Phase Relations, 11)... 

Fra] Fraker, A.C., Stadelmaier, H.H., The q Carbides of Molybdenum-Iron, Molybdenum-Cobalt and Molybdenum-Nickel , Trans. AIME, 245, 847-850 (1969) (Phase Diagram, Crys. Structure, Experimental, Morphology, 20)... 

Wever, E, Hashimoto, U., About the Binary Cobalt-Chromium System, With a Contribution to the Knowledge of the Qualities of Cobalt-Chromium Alloys, and an Appendix About the Influenee of Some Elements on the Qualities of the Cobalt-Chromimn Alloys (in German), Mitt. K. W Inst. Eisenforschung, 11, 293-330 (1929) (Experimental, Phase Diagram, Phase Relations,, , 50)... 

Mue] Mueller, P., Transforming Report of Iron-Chromium-Cobalt Alloys (in German), Neue Huette, 29, 268-270 (1984) (Experimental, Phase Diagram, Meehan. Prop., 4)... 

Ish] Ishida, K., Nishizawa, T., The Co-Cr (Cobalt-Chromium) System , Bull. Alloy Phase Diagrams, 11(4), 357-370 (1990) (Phase Diagram, Phase Relations, Review, 56)... 

---