Application and process
Compared with hexavalent chromium plating, trivalent chromium plating is environmentally friendly, which makes the demand for trivalent chromium plating increase year by year. In the process of trivalent chromium plating, it is very important to prevent the oxidation of Cr3+ to Cr6+ and avoid pollution to bath solution. Traditional lead-base alloy anode or graphite anode is not suitable for trivalent chromium plating due to its high oxygen evolution potential. The titanium anode with iridium mixed metal oxide coating has low oxygen evolution potential, which effectively inhibits the oxidation of Cr3+ and ensures the stability of the plating solution. Moreover, titanium anode characterized by excellent conductivity, uniform current distribution and excellent electrolyte corrosion resistance is the best conductive electrode for trivalent chromium plating.
Typical application conditions
Advantages
Promote the dispersion of metal coating
No or less Cr6+ ions are generated, to avoid the pollution of bath solution
No anode slime is generated, to ensure the cleanness and stability of the plating solution
Low voltage, high current efficiency, energy saving of plating bath
Good corrosion resistance and thermal shock resistance.
| Main application areas | Anodes and coatings | Details |
| Cathodic Protection | KERAMOX® Titanium anode Platinised Titanium Anodes based on Niobium or Tantalum | All round applicable At high current densities, for example in sea water High voltages or strongly corrosive electrolytes |
| Seawater electrolysis | KERAMOX® Titanium anode Titanium with a Ruthenium Mixed Metal Oxide coating Titanium with a Platinum-Iridium Oxide coating | Depending on amongst others temperature and salinity |
| Electroplating | Titanium with an Iridium Mixed Metal Oxide coating Platinised Titanium | In highly acidic environments such as: Electro galvanising (zinc plating) Anodising of Aluminium Chromium, Nickel,Tin, etc. plating Precious metal plating Reverse pulse Copper plating Hard Chromium plating Precious metal plating |
| Water treatment | Platinised Titanium Titanium with an Iridium Mixed Metal Oxide coating Boron-Doped-Diamond anodes | Electro dialysis with polarity reversal Recovery of metals Oxidation and break-down of organic contaminations Higher overpotentials,amongst others for disinfection |
| Hypo chlorite & Disinfection | Titanium with a Ruthenium Mixed Metal Oxide coating Titanium with an Iridium Mixed Metal Oxide coating Titanium with a Platinum-Iridium Oxide coating | Depending on salinity, polarity reversal and current density |
| Synthesis reactions | Platinised Titanium Titanium with an Iridium Mixed Metal Oxide coating Boron-Doped-Diamond anodes | Depending on the particular reaction At higher overpotentials |
| Hydrogen production | Nickel electrodes with a precious metal coating | Coating process by means of exchange plating The purpose is to decrease the overpotentials |