Cashew Nut Shell Liquid as an Anticorrosive Agent in Ceramic Materials

One of the significant challenges of the ceramics industry is to increase the corrosion resistance of ceramic materials, and the study of this corrosion requires a detailed investigation using several characterization methods, such as the knowledge of technological properties including the absorption, apparent porosity, and mechanical resistance of these ceramic materials. This corrosion resistance can be further improved by using a protective coating on the surface of ceramic materials, such as cashew nut shell liquid (CNSL), which has been used as a green, environmentally friendly corrosion inhibitor. This work investigated the inhibitory action of CNSL on the corrosion of ceramic materials. Clay from the Brazilian Northeast was used in a simulated seawater environment at room temperature for the immersion corrosion test. Sets of prismatic specimens bathed in CNSL were immersed in a corrosive solution and compared with other samples without CNSL immersed in a corrosive environment. At the end of 70 days in corrosive solution, the ceramic specimens without CNSL showed signs of wear on the surface, associated with an average mass loss of 20 mg and an average corrosive rate of 0.017 mm/year. On the other hand, the bodies bathed in CNSL showed no mass loss, reinforcing the potential of CNSL as a protective agent against corrosion.