1996 Volume 45 Issue 1 Pages 17-22
Laser surface melting (LSM) treatment using continuous wave CO2 laser was applied for improvement of general corrosion of nodular graphite cast iron and grey cast iron. Corrosion behavior of as-melted surface and reheated suface were evaluated by immersion and potentiodynamic tests. A chill surface layer was formed due to rapid solidification in applying LSM treatment, and corrosion rate in 0.05kmol/m3-H2SO4 solution decreased except heat affected zone. By LSM treatment, current density decreased in passive range in anodic polarization curves, which coincided with immersion test. This improvement of corrosion resistance by LSM treatment is caused by the disappearance of graphite due to rapid solidification. Resistance to general corrosion of LSM specimen was maintained by reheating treatment, which coincided with anodic polarization curves.
