Interdiffusion Coefficients of Fe and Si Measured from Si/IF Steel Coating System

Abstract

We adopted sputtering techniques to produce Si thin films on IF (interstitial free) steel sheets in this study to obtain diffusivity of O and interdiffusion coefficients of Si and Fe in sputtered Si film. The microstructure of the coating system was analyzed by using XRD (X-ray diffractometry) and Raman spectroscopy. The compositional variations and the phase transformation within the diffusion zone at the end of diffusion annealing were inspected by employing GDOS (glow discharge optical spectrometry) and XPS (X-ray photoelectron spectroscopy). The diffusivities of Fe and Si for the Si-Fe diffusion couple calculated based on the Boltzmann-Matano method and the depth profiles from GDOS were found to vary from 2.40×10⁻¹⁵ to 4.24×10⁻¹⁴ cm²/s and 5.77×10⁻¹⁵ to 6.59×10⁻¹⁴ cm²/s, respectively. The diffusivity of O in the Si thin film, 2.19×10⁻¹⁴ cm²/s, was however obtained by employing Grube method. Low diffusivities of O and Fe within the Si film are the reason why sputtered Si film is suitable to serve as an anti-oxidation barrier for the IF substrate at 400°C.

Keywords:

• IF steel
• sputtered Si film
• GDOS
• diffusivity
• Boltzmann-Matano method
• Grube method