PANi/CaCO3 as Anti-corrosive Coating


Indonesia is a country with volcanoes that have high potential geothermal energy content (40% of world reserves). In the geothermal exploration in North Sulawesi, there was a blockage in the geothermal well pipes, which were corroded by geothermal environments. Most of the deposited sediment is silica sand which overlaps the fluid in the geothermal environment. Now, a lot of research is being done to find anticorrosive materials in geothermal environments. The Corrosion research group conducts material research which develop some anti-corrosion coating materials. Several types of material studied were Al / SiO2, PANi / CaCO3 and PANi / SiO2 composite materials. Polyaniline based (PANi) based composite materials with particle calcium carbonate (pcc-CaCO3) and Silica (SiO2) as fillers with varying structures as anticorrosive coatings on steel. Filler materials are synthesized from natural materials namely limestone and silica sand using the method hydrothermal and coprecipitation, respectively. The composition and structure of both CaCO3 or SiO2 as fillers have good corrosion resistance properties and are significant to the synthetic geothermal environment and high salinity.



Microstructure of synthesized CaCO3 using carbonation methode




Nyquist diagrams of PANi/CaCO3 composite layer after corrosion in NDB solution at room temperature showed that the PANi/CaCO3 calcite phase has a better corrosion resistance than the PANi/CaCO3 other phases




The corrosion rate of PANi/CaCO3 composites with variation phases (Calcite, Vaterite and Aragonite). The PANi/CaCO3 calcite with 2.5 w/w concentration has a best corrosion resistance.