Resumen de Effect of spinels on the mechanical and tribological behavior of plasma sprayed alumina based coatings

Álvaro Rico García, Alicia Salazar, Claudio José Múnez Alba, Davide Verdi, Miguel Escobar Torres, Pedro Alberto Poza Gómez, Jesús Rodríguez Pérez

• Plasma sprayed ceramic coatings are widely used to protect metallic substrates when high temperature and/or friction are developed in service. In particular, alumina based coatings have been extensively used. Examples of applications are pistons in pumps or internal combustion engines and steam valve spindles. Alumina is hard, it shows a very high oxidation resistance and it is not permeable to aggressive gases. However, the alumina main drawback is its low fracture toughness. Brittle fracture is one of the most common wear mechanisms reported for ceramics. It is well known that the fracture toughness and the operative conditions are the key parameters controlling the crack propagation throughout the material. As a consequence, transition from mild to severe wear in ceramic coatings is mainly controlled by the fracture toughness of the coating. The typical solutions to improve the fracture behavior of alumina coatings are based on mixing alumina powders with other ceramic ...