We are specialised in creating world class coatings for multiple purposes. Let's take a look at how we do it:
All electrodes are made from a base and a coating.
The coating is similar in certain aspects to a varnish, but deeply different in composition and application method and its purpose is to make possible the electrochemical reactions.
The coating needs a support it is applied on and which supplies it with the necessary mechanical structure which constitutes the electrode.
Among the many materials tested, our choice of the support, or substrate as it is called in scientific language, has fallen on Titanium.
Titanium has the features required to receive the coating, to resist the chemically aggressive environments of the processes and is suitable for the current’s conduction.
Additionally Titanium can be worked in a wide range of shapes: sheets, nets, tubes, wires, complex manufactured products etc.
The electrode is created from the combination of the coating and the Titanium, and then takes different commercial names such as MMO etc...
The main benefit is that it remains unaltered in time and that only the coating wears out slowly. An electrode which has lost all or part of the coating during its life can be regenerated with subsequent applications an undefined number of times.
The electrode can be used, depending on the process it’s designed for, both as cathode and anode.
Used as cathode, for example in the membrane chlorine – Alkali process, the base is in Nickel, whereas the coating maintains its noble metals-based composition.
A very thin layer, of just a few microns, that covers the titanium’s surface where the anodic reaction takes place.
It’s made of oxides of noble metals part of the Platinum family.
Ruthenium and Iridium are the main elements we use, mixed with others within the same family: Palladium, Rhodium, Platinum.
The Titanium family’s oxides are part of the coating’s formula as well: Titanium, Tantalum, Niobium. They serve the purpose to make the structure more compact and adherent to the Titanium base and at the same time provide a protective function against the aggressiveness of some solutions the electrodes need to work in.
The formation of the coating takes place through the application of a solution of the above described elements and a subsequent high temperature thermal treatment to create the oxide.
Each application or “coat” is a cycle during which a fraction of the prearranged coating’s quantity settles. The number of cycles is subject to the final noble metal’s load, which, in turn, is in relation to the type of final use it’s designed for.
There are many formulations or “recipes” for coating, each of which is specific for its final use.
There are two main families: anode and cathode coating.
Among the anode coatings you can distinguish: coatings for Chlorine evolution, coatings for Oxygen evolution or mixed coating.
The key component or the “catalyst” of the coating for Chlorine evolution is Ruthenium Oxide; for Oxygen evolution we use Iridium Oxide.
Membrane cell cathode coatings are based on Ruthenium Oxide or Platinum, mixed with Palladium, Rhodium.
A coating for each process
The main use of the coating is related to the anodes, as cathodes are often built with materials of different composition.
There are two main anodic reaction families and they are:
The production of Chlorine (Cl2) from solutions containing Chlorides (Cl-) according to the electrochemical reaction:
Cl- + e- ----> Cl2
the production of Oxygen (O2) from acid solutions containing mainly Nitrates, Sulphates according to the electrochemical reaction:
2H2O ----> O2 + 2e- + 2H+
The most important industrial applications Chemical Newtech refers to are:
Anodes for Chlorine:
Chlorine – Caustic Mercury Cells
Chlorine –Alkali Diaphragm Cell
Chlorine-Alkali Membrane Cells
Electrolysers for Hypochlorite production
Electrolysers for Chlorate production
Electrochlorinators for swimming pools
Metal Winning from Chlorides
Anodes for Oxygen:
- Decorative plating
- Hard plating
- Rhodium plating, Gilding
- Copper plating, Nickel plating
Anodes for cathodic protection