Caracterização microestrutural e avaliação da resistência à corrosão da liga FeNb para aplicação em petroquímica

Abstract

The petrochemical industry currently presents a range of operational challenges, and among these, the presence of extremely aggressive environments stands out, which contribute to the premature wear of metallic components, thus creating the need for materials with high corrosion resistance and good thermal stability. In this context, the ferroniobium (FeNb) alloy emerges as a promising alternative, presenting the necessary requirements to withstand the operational conditions present in this industry. This work aimed to analyze the performance of the FeNb alloy in an acidic medium, similar to that found in the petrochemical industry, through the analysis of corrosion resistance and microstructural characterization. For this, the experimental procedure consisted of obtaining an ingot from granulated FeNb, followed by sample preparation via metallography and, subsequently, an immersion corrosion test in which the alloy was exposed to 1M hydrochloric acid (HCl) for 24 h. Furthermore, microstructural and compositional analyses were carried out using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X ray diffraction (XRD), aiming to identify the phases formed, along with their respective compositions and possible structural changes. The results showed a heterogeneous and refined structure, composed of intermetallic phases typical of the FeNb alloy, such as Fe21Nb19 (μ), Nb (e2), and Fe2Nb (e3), together with the possibility of forming an amorphous Nb2O5 passive layer, which provided good corrosion resistance and structural integrity, combined with low corrosion rates. Thus, the results obtained reinforce the viability of using the FeNb alloy in aggressive environments, suggesting its applicability in the petrochemical industry.