Geology

Conversion coating

Nanotechnology

Coating

Oceanography

Composite material

Metallurgy

Materials science

Chromate conversion coating

Corrosion

Substrate (aquarium)

Titanium

Adhesion

Zirconium

Journal of The Electrochemical Society

There is a growing interest in conversion coatings based on titanium and/or zirconium as the result of the health and environmental issues associated with legacy chromate and phosphate conversion coatings. Any alternative technology should be environmentally friendly and cost effective, and also able to achieve comparable corrosion resistance and paint adhesion for ferrous and non-ferrous substrates. Conversion coatings based on titanium or zirconium seem to fulfill many of these requirements and thus offer a great potential for further applications. This literature review summarizes the scientific results in this rapidly growing area of research. Following the description of composition of conversion bath and deposition mechanism, the effects of process parameters for conversion baths such as pH, temperature, immersion time and agitation are presented together with coating characteristics. The effects of the type of substrate and substrate pre-treatment are explored for the most-studied substrates: Al alloys, zinc-coated steels and steels. Properties such as composition, morphology and thickness are summarized. The corrosion performance of the conversion coatings is discussed, as well as adhesion of organic coatings and delamination mechanism for a full coating system including substrate/coating/top-coat.

Review—Conversion Coatings Based on Zirconium and/or Titanium