Avaliação de desempenho de geopolímero utilizado como revestimento protetor do aço

Abstract

Environmentally friendly and sustainable protective coating materials with improved performance have been highly sought after by all industrial sectors. Among these coatings, we can mention geopolymer coatings that are formed from an exothermic reaction between an alkaline activator and an aluminosilicate precursor, and have emerged as a potential base for protective coatings for metallic substrates. The objective of this work was to evaluate the performance of a geopolymer material as a protective coating on SAE 1006 and 1020 carbon steel specimens. After oven curing of the coating layer in the metallic samples, defects were observed, including fragility, pores and cracks, which gave rise to the idea of applying a second coating layer to the samples. In the visual aspect, the second layer was more homogeneous and made the substrate more protected, as it did not present bubbles and cracks visible to the naked eye. The saline mist test, for samples in SAE 1006 steel, problems of adhesion of the coating to the substrate were identified, showing corrosion points in all samples in the first 48 hours of testing. The samples in SAE 1020 steel with the application of the second coating layer showed excellent corrosion resistance during the test period of 240 hours. The roughness presented by both SAE 1006 and SAE 1020 steels is directly related to the positive results obtained, considering that the SAE 1020 steel sample is rougher and had better coating adhesion. The tests carried out show that the geopolymer coating presented reasonably satisfactory results under the conditions studied, however suggestions for future work are presented regarding the application of the geopolymer and the most suitable metallic substrate. [resumo fornecido pelo autor]