Yuan, Z., Xiao, J., Wang, C. et al. Preparation of a superamphiphobic surface on a common cast iron substrate. J Coat Technol Res 8, 773 (2011). https://doi.org/10.1007/s11998-011-9365-7

I don't have a subscription or SciHub link to pull up the underlying, but it looks like there have been folks who did electron microscopy on seasoned cast iron. (Note: more relevant and profitable to study in the context of machinery / engine design)