Abstract
The volume influence of aqueous sulfuric acid solution on the corrosion rate of pure iron during the initial 0.6ks was investigated by potentiostat, digital microscope and atomic force microscope (AFM). Three types of solution volume on the specimen, bulk solution, macro-droplet with millimeter size and micro-droplet with micrometer size, were used.
A micro-droplet with diameter of 1~10 μm can be produced on a pre-assigned target micro-zone of specimen by the cantilever tip of AFM. The corrosion behavior by the droplet can be investigated using both the contact mode and the AC non-contact mode of AFM. The corrosion rate in bulk solution was much higher than that in a micro-droplet of sulfuric acid solution. In the case of corrosion on pure iron surface caused by a micro-droplet, the corrosion rate was smaller for the smaller droplet. The solidification of the micro-droplet in 25-30%RH condition is faster than that in 50-70%RH condition.
