Initial Stage Carbonization of γ-Fe(100) Surface in C₂H₂ under High Temperature: A Molecular Dynamic Simulation

Area of Science:

• Materials Science
• Surface Science
• Computational Chemistry

Background:

• Understanding the initial stages of carbonization on metal surfaces is crucial for developing advanced materials.
• Iron-based alloys are widely used, and their surface properties under carbon exposure are of significant interest.

Purpose of the Study:

• To elucidate the atomic mechanism of the initial carbonization of a γ-Fe(100) surface using acetylene (C2H2).
• To analyze the effect of temperature on carbon and hydrogen atom absorption and diffusion.
• To investigate the influence of polycrystalline γ-Fe on the carbonization process.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model the carbonization process.
• Simulations covered a temperature range from 1000 K to 1600 K.
• Analysis focused on atom absorption, diffusion, and distribution within the carbonized layer.

Main Results:

• Higher temperatures were found to enhance the inward diffusion of carbon (C) and hydrogen (H) atoms.
• Elevated temperatures also led to the desorption of H atoms from the surface.
• Polycrystalline γ-Fe demonstrated a promoting effect on the absorption and internal diffusion of C and H atoms.

Conclusions:

• The study provides insights into the atomic mechanisms governing the initial carbonization of iron surfaces.
• Temperature plays a critical role in controlling C and H atom behavior during carbonization.
• The findings can contribute to the optimized design of high-performance steels.