MICRO-ROMAN SPECTROSCOPY OF RUST LAYER OF LOW CARBON STEEL EXPOSED TO ATMOSPHERE

The effect of phosphorus on corrosion resistance of low carbon steels was investigated by micro-Raman analysis.The rust layer of low carbon steel exposed to simulated atmosphere was composed of double layers.The inner layer was mostly covered with α-FeOOH,and the outter layer was covered with α-Fe2O3 and γ-FeOOH.The obvious difference between tested steels bearing different P contents was as follows.The rust layer of higher P bearing steel was thiner and compacter,and it was almostly covered with dark inner rust layer,while the rust layer of lower P bearing steel was thicker,and a plenty of white outer rust layer existed.