Carbon-silicon phase diagram

A cross-section of a modified surface is shown in Fig. 13.4. The schematic of the modifying process is shown in Fig. 13.5 and Figs 13.6 and 13.7 show the iron carbon diagram for austenitic T91 at 1050°C and 0.1%C, and the iron-silicon phase diagram with phase transformation from austenitic to ferrite steel lattice with growing Si content, respectively. 

The crystalline core can make SiNW either fairly straight, or coiled or curly. It was discovered that CH4 may affect the helicity. This may be caused by a more complicated phase diagram that involves carbon, silicon, and metal. 

A phase diagram for the carbon—silicon system and for the relationship between temperature and solubility of carbon in silicon has been determined... 

The thermodynamics of the above-elucidated SiC/C and SijN Si composites are determined by the decomposition of silicon carbide and silicon nitride, respectively, into their elements. The chemistry of ternary Si-C-N composites is more complex. If producing Si-C-N ceramics for applications at elevated temperature, reactions between carbon and silicon nitride have to be considered. Figure 18.2, which exhibits a ternary phase diagram valid up to 1484°C (1 bar N2) displays the situation. The only stable crystalline phases under these conditions are silicon carbide and silicon nitride. Ceramics with compositions in the three-phase field SiC/Si3N4/N are unknown (this is a consequence of the thermal instability of C-N bonds). Although composites within the three-phase field SiC/Si3N4/Si are thermodynamically stable even above 1500°C, such materials are rare. The reasons are difficulties in the synthesis of the required precursors and silicon melting above 1414°C. The latter aspect is of relevance, since liquid silicon dramatically worsens the mechanical properties of the derived ceramics. 

Figure 4.5 shows a phase diagram between silicon and carbon. The diagram shows how SiC particle precipitation forms in Si-melt in the C-rich domain [20], in which the solubility limit of carbon in Si-melt CL(T) is approximated by a polynomial function,... 

E. Rudy, Ternary phase equilibria in transition metal-boron-carbon-silicon systems. Part V. Compendium of phase diagram data. Tech. Rep. AFML-TR—Air Force Mater. Lab. (US.) AFML-TR-65-2 (1969). 

Calculations of the Si-C system were presented by Kaufinan (1979) [113] and Olesinski and Abbaschian (1984) [88]. Lim and Lukas (1996) [36] published a thermodynamically optimized dataset which was refined by Grobner (1996) [35]. This dataset is accepted by the present evaluators. The accompanying calculated phase diagram is shown in Fig. 3. SiC decomposes to graphite and carbon-rich liquid silicon at a temperature of 3095 K. 

Figure 3. Phase diagram of the silicon-carbon system at 1 bar total pressure after Kleykamp and Schumacher [12].

Rudy, E. Ternary Phase Equilibria in Transition Metal-Boron-Carbon-Silicon Systems, Vol. V, Compendium of Diagram Data, US Atomic Energy Comm. Publ. AFML-TR-65-2, Wright Patterson Air Force Base, OH, 1969. 

Soe] Soehnehen, V.E., Piwowarsky, E., About the Influence of Alloying Elements Nickel, Silicon, Aluminium and Phosphorus on the Carbon Solubility in Liquid and Solid Iron (in German), Arch. Eisenhuettenwes., 5(2), 111-121 (1931) (Experimental, Morphology, Phase Diagram, 51)... 

Hon] Honda, K., Murakami, T., On the Structural Constitution of Iron-Carbon-Silicon Alloys , J. Iron Steel Inst, 107, 545-583 (1923) (Magn. Prop., Morphology, Phase Diagram, Thermodyn., 19)... 

Sal] Saltykov, S.A., Stable Phase Diagram Iron-Carbon Alloys with Silicon (in Russian), Litey-noe Delo, 10-11, 15-16 (1939) (Review, Phase Diagram, Phase Relations, 4)... 

Jae] Jaenecke, E., About half Two Phase Diagrams of the Iron-Carbon System and their Relationships in Ternary Alloys, in Partieular by Silicon (in German), Z. Metallkd., 32(5), 142-144 (1940) (Abstract, Phase Diagram, Phase Relations, 23)... 

Smi] Smith, R.P., Equihbrium of Iron-Carbon-Silicon and of Iron-Carbon-Manganes Alloys with Mixtures of Methane and Hydrogen at 1000°C , J. Am. Chem. Soc., 70, 2724-2729 (1948) (Experimental, Thermodyn., Phase Diagram, 20)... 

Chi] Chipman, J., Alfred, R. M., Gott, L.W., Small, R.B., Wilson, D.M., Thomson, C.N., Gue, D.L., The Solubihty of Carbon in Molten Iron and Iron-Sihcon and Iron-Manganese Alloys , Trans. Amer. Soc. Metals, 44, 1215-1232 (1952) (Experimental, Phase Relations, 16) [1952Hil] Hilhard, J.E., Owen, W.S., A Thermal and Microscopic Study of the Iron-Carbon-Silicon-System , J. Iron Steel Inst, 172, 268-282 (1952) (Experimental, Morphology, Phase Diagram, 28)... 

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