What is the resistivity of soil?
The soil resistance (soil resistivity) is expressed in Ohm.cm or Ohm.m. In general, a rough indication of the corrosiveness of the soil compared to the soil resistivity is given Soil resistivity (Ohm.cm) Example Corrosivity < 2000 Peatlands, forest grounds Highly corrosive 2.000-5.000 loam soil Corrosive -highly corrosive 5.000-10.000 Silt sand Moderate corrosive > 10.000 Dry […]
What is the required potential for cathodic protection?
How many anodes should I place? At what voltage should I set the ICCP system? It all comes down to the question of what potential is necessary to protect the object. This, of course, depends on the type of material. Alloy steels require a different protection potential than pure iron. The pourbaix diagram is an […]
What is cathodic protection?
The principle of Cathodic Protection (CP) is to lower the corrosion potential of a metal object. This can be done with a protective current or by using sacrificial anodes. In both cases, the metal to be protected is made cathodic and thus impervious to corrosion. Corrosion is a chemical reaction where the metal reacts and […]
Electrochemical potentials of metals against the theoretical hydrogen electrode and the Cu/CuSO4 reference electrode
Each metal has their own balance potential in there isolated electrolyte. This material property makes the metal more noble or less noble. In other words, it becomes more or less susceptible for corrosion to occur. When a salt solution with a fixed concentration of own metal ions is created, the theoretical electrochemical potential can be […]
What is the cathode? And what is the anode?
The cathode is the electrode where the direction of the electric current is from the electrolyte (soil, water) towards the metal object to be protected. The anode is the electrode where the direction of the electrical current is from the metal object to the solution. Do you recognise it? Many people tend to forget the […]
The 5 Most important methods to measure external coating defects on pipelines (without excavation)
There are several above ground techniques with which it is suffucient to walk and measure coating defects over the entire lenght of the pipeline. A great advantage of these techniques is that you don’t need to perform destructive measurements or to excavate the pipeline. The 5 most common techniques are: Pearson technique Close Interval Potential […]
Is my coating system good for Cathodic Protection?
This mainly depended on the amount of electrons that can be passed through the coating system. This is defined as electrical conductivity. A coating systems that has a very high (electrical) resistance can be defined as an isolating coating system. Examples are asphalt/bitumen and polyethylene (PE) based coatings. On the other hand, there are coating […]