Chromium diagrams

Many stainless steels, however, are austenitic (f.c.c.) at room temperature. The most common austenitic stainless, "18/8", has a composition Fe-0.1% C, 1% Mn, 18% Cr, 8% Ni. The chromium is added, as before, to give corrosion resistance. But nickel is added as well because it stabilises austenite. The Fe-Ni phase diagram (Fig. 12.8) shows why. Adding nickel lowers the temperature of the f.c.c.-b.c.c. transformation from 914°C for pure iron to 720°C for Fe-8% Ni. In addition, the Mn, Cr and Ni slow the diffusive f.c.c.-b.c.c. transformation down by orders of magnitude. 18/8 stainless steel can therefore be cooled in air from 800°C to room temperature without transforming to b.c.c. The austenite is, of course, unstable at room temperature. Flowever, diffusion is far too slow for the metastable austenite to transform to ferrite by a diffusive mechanism. It is, of course, possible for the austenite to transform displacively to give... 

Fig. 7.71 An activity diagram showing the competing formation of sulphides and oxides on chromium. The XPS data (lower) show how sulphide replaced oxide as the surface anion when oxide samples were heated in the gas composition marked on the O-S diagram, implying that the boundary should be moved. (Reprinted with permission from Pergamon Press after...

The iron-chromium constitution diagram is shown in Fig. 12.19. At around 1 000°C, it can be seen that when chromium is deposited and diffused... 

Consider a salt bridge cell in which the anode is a manganese rod immersed in an aqueous solution of manganese(II) sulfate. The cathode is a chromium strip immersed in an aqueous solution of chromium(in) sulfate. Sketch a diagram of die cell, indicating the flow of the current throughout. Write the half-equations for the electrode reactions, the overall equation, and die abbreviated notation for the celL... 

Part (d) asks for an energy level diagram for this process. The electron starts in the ground state. On absorption of a photon, the electron moves to an energy level that is higher by 239 kJ/mol. The chromium ion loses 28.0% of its excited-state energy as heat as the electron moves to a different level... 

C07-0053. Draw energy level diagrams that illustrate the difference in electron binding energy between cesium metal and chromium metal. Refer to Problems and. ... 

Fig. 2. Potential diagram of the redox couples of chromium. According to Csanyi . References pp, 577-580...

Figure 4.11 The stability diagram for the chromium-oxygen-carbon system at 1245 °C.

The process flow diagram consists of chromium reduction, chemical precipitation, and clarification. 

X-ray powder diagrams obtained by the Guinier method show the tris (O-ethyl dithiocarbonato) complexes of chro-mium(III), indium(III), cobalt(III), iron(III), arsenic(III), and antimony(III) to be isomorphous. Carrai and Gottardi have determined the structure of the arsenic(III)18 and anti-mony(III)19 complexes. Crystallographic data for the cobalt(III) and chromium(III) ethylxanthate complexes are given by Derenzini20 and Franzini and Schiaffino,21 respectively. 

Since the rate of formation of cementite is determined by nucleation, and therefore proceeds more rapidly in fine-grained steels, it follows that the T-T-T diagram will show a more rapid onset of austenite decomposition than in steels of the same composition, but a coarser grain size. The shape of the T-T-T curve is also a function of the steel composition, and is altered by the presence of alloying elements at a low concentration. This is because the common alloying elements such as manganese, nickel and chromium decrease... 

G. Ghosh, Aluminium-chromium—copper, in Ternary Alloys A Comprehensive Compendium of Evaluated Constitutional Data and Phase Diagrams, G. Petzow and G. Effenberg, Ed., VCH Publishers, New York, 1992, pp. 311-319. 

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