Novel non-hydroxyl synthesis and fabrication of advanced hybrid inorganic-organic geopolymeric coating material for corrosion protection

Abstract The objective of this paper was to fabricate advanced geopolymeric coating materials having advanced hybrid inorganic-organic characters (using novel solid state geopolymerization processes), which can effectively protect mild steel substrates from the damaging effects of corrosion. To achieve this objective, different geopolymeric mix designs were formulated using fly ash as an amorphous silicoaluminous source and rice husk as a source of organic components and other raw materials. The developed materials were coated on the substrate via a paint brush technique. In order to understand and correlate coating performance, fabricated hybrid geopolymeric coatings were first tested for adhesive strength and then for water resistance and corrosion resistance properties. A geopolymer-epoxy composite was also prepared using epoxy resin as yet another hybrid organic additive and results indicated the superiority of this composite in terms of adhesion and other studied properties. The microstructures, thickness and elemental composition of different geopolymeric coating compositions were studied using FESEM and EDX spectral analysis. Results revealed that rice husk addition to geopolymeric matrix not only enhanced gelation but also contributed to good adhesion and excellent corrosion protection for the underlying substrate. A geopolymer-epoxy composite on other hand, owing to its high crosslinking structure, performed extremely well for all parameters. Fabricated hybrid geopolymeric coating material find its application as corrosion protective coating for different industries to ensure metal durability and reduction in unwanted maintenance cost.