Caracterización de Revestimientos de Niobio formados por Aspersión Térmica a Plasma sobre Acero API 5l X65

Abstract

The morphology and electrochemical behavior of niobium coating obtained by thermal plasma spray process on a substrate of steel API 5L X65 was evaluated. The coating was obtained, using electrical current of 500 A, 15 g/min of powder and 2.0 L/min of argon gas. The preparation of the substrate surface was performed with preheating and abrasive blasting with alumina. After thermal spraying, the morphology of the coating was analyzed by scanning electron microscopy (SEM), while the surface roughness was evaluated by profilometry, hardness by Vickers microhardness test and adhesion by bending at 180°. The corrosion resistance of the coating was evaluated from the polarization test in 3.5% NaCl solution. The results show that the coating presented cracking and lack of padding between the plates sprayed, relative high hardness and deficient adhesion to the substrate. However, the values of current density carried by the system compared to uncoated steel were reduced.