Corrosion Behaviour of Nitrided 904L Stainless Steel with Damaged Surface in Hydrofluoric Acid

Surface indentations were prepared by microhardness tester. Using optical microscope (OM), scanning electron microscope (SEM) and confocal laser scanning microscope (CLSM), the corrosion behavior of nitrided 904L stainless steel with and without damaged surface in 1 mol/L HF solution were analyzed. The results show that the undamaged nitride layer had a good protective effect on the the substrate. The damaged nitrite layer would not fall off in a large area as the corrosion progressed. Corrosion occurred preferentially in the crack area of nitride layer under the action of long-term erosion. The corrosion rate of nitrited sample was lower than that of blank sample.