From time to time it becomes necessary to remove metal oxide. It is done by the observing the dissolution of FE in the solution used for this purpose. As iron oxide get dissolve, the absorption of melted FE raises in the beginning in the solution. It is first step of derouging process. Before that removal of the residue can’t be done effectively.
In course of time, a relatively steady worth of liquefied FE indicates the end of process. With the help of wide range of methodical techniques, the concentration of the dissolved Fe is monitored. However, the most convenient techniques in the process is atomic absorption or spectrophotometry.
One can monitor all these processes in two ways:
- Monitoring the elimination of the oxide deposit
- Measuring the corrosion rate with the expansion of passivation
Finally, the defensive passive film is set apart with the help of the techniques of the surface susceptibility. Since derouging is the product of contact surface in different phases, these are done under the observation of electrochemical method. This method indicates the proneness of the metallurgy to any given solution or environment. For a constant potentiality, the rate of corrosion is relative to the existing measurement.
Though several electrochemical methods are used to observe the corrosion reaction the two most functional and constructive techniques are the Linear polarization and the potentiodynamic polarization.