Progress in bifunctional coatings modulated by novel cost-effective core-shell nanopigment

Abstract With the progress of nanotechnology and increasing global demands, multifunctional coatings based on nanomaterials are becoming incredibly attractive owing to the possibility of offering a unique combination of several features. The key to this work is to explore the potential of feldspar as a source for value-added materials, particularly through the innovative modification of its surface with nano-nickel ferrite to provide anticorrosive and thermally stable bifunctions in a single coat layer. Herein, a novel bifunctional core-shell nanopigment (NiFe/feldspar) was synthesized via deposition of a thin layer of nanonickel ferrite (an expensive pigment) on cheap feldspar, which has the greatest abundance in the crust of the earth. Besides, pure nanonickel ferrite (nano-NiFe) was prepared to compare the performance of NiFe/feldspar core-shell nanopigment to that of nano-NiFe. After their synthesis and characterization, silicon resin was modified with two ratios of nano-NiFe or NiFe/feldspar (e.g., 16.5 and 33 wt%) to replace an expensive aluminum pigment in the commercial coating and to evaluate their corrosion resistance and thermal stability. The findings showed that film with 33% NiFe/feldspar can offer superior anticorrosive performance with sustained resistance ranging from 5,270,083 Ω.cm 2 to 2,030,197 Ω.cm 2 through 28 days of immersion in 3.5% NaCl. Additionally, the results demonstrate the superior thermal resistance of a matrix containing 33% NiFe/feldspar. Furthermore, the insertion of nano-NiFe pigment and NiFe/feldspar core-shell nanopigment with both ratios enhanced corrosion and thermal resistance more than the commercial coating.