Anti-corrosive pigment project


Atmospheric corrosion on the metal surface it’s in fact electrochemical process of anodic oxidation of metal and cathodic reduction of the atmospheric oxygen, known as cathodic depolarization. The basic corrosion inhibitive mechanisms are:

  • active corrosion protection – is a shift of the potential of the metallic substrate in the passive area,
  • passive corrosion protection – which consists of three main mechanisms : barrier function (cutoff atmospheric corrosive agents), the adhesion of the coating (to prevent formation of an electrolyte layer on the substrate) and the inhibiting effect of anti-corrosive pigment.

The barrier and adhesion properties depend mainly on the type and quality of applied binder/resins. Most popular binders used are: alkyd, acrylic, epoxy, polyurethane, polyvinyl. Active pigments (except the most widely used zinc phosphate (V)) are, zinc molybdate, borates and borosilicates, or zinc oxide. In addition to these inorganic materials research and experience of coating industry companies show that very interesting group of prognosis and active pigments are conductive polymers.

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Anti-corrosive activity of NanoPure conductive polymers

The mechanism of corrosion properties of conducting polymers in the protective coatings is widely discussed by scientists. Currently there are two most probable mechanisms of conducting polymers corrosion protection:

  • pushing the potential of the metallic substrate in the passive area, allowing the formation of protective layer on the surface of the metal
  • increase in the electrical conductivity of the entire protective layer, which transfers cathodic depolarization from the metal surface to the coating.

Activity results of polymer based anti-corrosive pigment

Conducted basic research showed that the addition of 0.5% to 1.0% mass of conductive polymer pigment in anti-corrosion alkyd paints significantly improves anti-corrosion protective effect of organic coating. Number of EIS (Electrochemical Impedance Spectroscopy) test were conducted where anti-corrosive effect of conductive polymer pigment with different concentration was assessed. Results are very promising with protection level few times higher comparing to traditional pigments. This is the basis for the projects that NanoPure is about to start to develop and commercialize a family of polymer based anti-corrosive pigments POLYCOR™