Particle-particle interface corrosion of cold sprayed copper in dilute nitric acid solution: Geometry-controlled corrosion mechanism

Abstract

The mechanism of particle-particle interface (PPI) corrosion observed in cold sprayed (CS) Cu immersed in dilute HNO3 has been elucidated. PPI corrosion is initiated by the oxide inclusions present along the PPIs. The accelerated corrosion rate at PPIs results from the combined effects of confined geometry and catalytic reactions, which involve the electrochemical dissolution of Cu and reduction of NO3−. Annealing the CS Cu at 600°C coalesces the oxide inclusions, thereby breaking the interconnected oxide inclusion network. As a result, the propagation of PPI corrosion is impeded.