Iron diagrams

MSIT] C-Fe (Carbon - Iron) , Diagrams as Published in MSIT Workplace, Effenberg, G. (Ed.), MSI, Materials Science International Services GmbH, Stuttgart Document ID 30.13598.1.20, (2006) (Phase Diagram, Phase Relations, Crys. Structure, 2)... 

The logs of the activities have been used in Figure 12-2 to produce the iron diagram. It shows clearly that attempts to obtain cell readings for Fe°-Fe(III) will fail because Fe(II) must first be produced in far higher activity than the Fe(III) to reach equilibrium. It shows that Fe(II) will be lowered below 1/1000 of the Fe(III) if an oxidizing titrant raises the E value of the solution above 1.0 V. It predicts suitable conditions for study of the equilibrium... 

Figure C2.7.1. Schematic potential energy diagram for tire catalytic syntliesis and decomposition of ammonia on iron. The energies are in kJ mol tire subscript ads refers to species adsorbed on iron [i].

Figure C2.8.1. Simplified /pH diagram (Pourbaix diagram) for the iron-water system at 25°C. The diagram is...

The diagram gives regions of existence, i.e. for a particular combination of pH and redox potential it can be predicted whether it is thennodynamically favourable for iron to be inert (stable) (region A), to actively dissolve (region B) or to fonn an oxide layer (region C). 

Fig. 1. Iron—carbon phase diagram, where a is the body-centered cubic (bcc) a-iron, y is the face-centered cubic y-iron, and Fe C is iron carbide(3 l)...

Fig. 5. Flow diagram depicting the principal units and auxiliaries in a modem blast furnace plant, and showing the steps in the manufacture of pig iron from...

Fig. 3. Schematic diagram of the iron blast furnace indicating some of the chemical reactions (3).

Heat Treatment of Steel. Steels are alloys having up to about 2% carbon in iron plus other alloying elements. The vast application of steels is mainly owing to their ability to be heat treated to produce a wide spectmm of properties. This occurs because of a crystallographic or aHotropic transformation which takes place upon quenching. This transformation and its role in heat treatment can be explained by the crystal stmcture of iron and by the appropriate phase diagram for steels (see Steel). 

The phases present in products can differ from those predicted from equilibrium diagrams. Nonequilibrium metastable phases form at solidification rates experienced in commercial ingots. Because of the low rate of diffusion of iron in alurninum, equilibrium conditions can only be established by long heat treatments and are very slowly approached at temperatures below about 550 °C. Small additions of other elements, particularly manganese, can also modify the phase relations. 

Fig. 16. Iron—iron carbide phase diagram (1). See text.

The Sulfate Process. A flow diagram for the sulfate process is shown in Figure 1. The strongly exothermic digestion of the dried, milled feedstock in 85—95°/ sulfuric acid converts metal oxides into soluble sulfates, primarily titanium and iron. 

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