In the diagrams below you can find corrosion levels of various materials in a strong halogen HCl/HF acid mixture (representative for many harsh corrosive conditions). Note, strong oxidizing agents such as HNO3 can often practice a protective effect on chromium or high chromium containing steel.

Both hard and corrosion resistant Lunac 1 and 2+ industrial coatings stay fully crack- and pore-free in the case the substrate is 1- free of serious defects and 2- ground smoothly in advance (Rz< 2.0 µm / 0.079 mil). The latest introduced technical hard nickel intermediate coating offers ultimate repair capability of surface micro-defects. Good corrosion resistance can not only be obtained by higher electro-potentials or dense oxide layers, but also by means of stress-free lattices, or even better, amorphous structures. In this way a material or coating with a lower electro-potential but crystal free structure can often deliver the same corrosion resistance as a more noble crystalline material. The additional advantage of such system is less galvanic corrosive activity and substantial cost savings. There are Lunac versions with no crystalline structure and small potential differences with steel. Moreover, hard coatings such as the Lunac systems which contains crack inhibiting compressive stresses are very rare. The latest Lunac 2+ duplex version even resists corrosion after plastic deformations because of the ductility of the intermediate technical hard nickel and the superb bond quality.

In reality coating damage due to accidents is likely to happen or coating / substrate transitions are present (end of coating). In a corrosive environment almost all protective noble (metallic) coatings will accelerate the steel (galvanic) substrate corrosion in these damaged spots. As a reference, passive organic coatings (paintings) show a neutral behavior. Lunac 2+ duplex coatings are optimized to come as close as possible to these passive coatings and do not show significant sub-surface corrosion.