| Title |
Effects of Alloying Elements in Iron Carbide formation |
| Abstract |
The diffusion of silicon and carbon atoms was studied in γphase of Fe-Si-C ternary alloy at 1000℃ under the steady-state condition. Diffusion cell assembly, essentially, consisted of a thin sheet of pure iron and a silicon powder (60 mesh) which was packed on one side of the membrane, while the other side was packed with manganese powder. Both sides of the pure iron membrane, were packed with 0.7 mm φcarbon rods to maintain the equal carbon potentials. Atomic rnobilitics of silicon were measured along each of the steady-state diffusion concentration profiles. Diffusion coefficient of silicon D_(22) was found to be, 39∼5.79×10^(-11) ㎠/s in Fe-2.8∼1.5 at. pct Si-2.2∼1.5 at, pct C system, where the diffusivity of silicon was increased by the addition of silicon and carbon atoms. Interstitial carbon atoms diffuse more rapidly than the substitutional silicon atoms. The carbon atoms on the gradient of slow moving component, will easily become a state of a transient equilibrium. The ratios of diffusivity of carbon D_(11) and cross term D_(12) were calculated by D_(12)/D_(11) ∼ 0.1∼0.19 at Yc=0.019∼0.021 in a Fe-Si-C alloy. |