Microstructure and corrosion behavior of Ti nanoparticles reinforced Ni-Ti composite coatings by electrodeposition

摘要

A survey on electrochemical codeposition of Ti nanoparticles in Ni matrix coating is given. The influences of Ti nanoparticle loadings in electrolyte on the microstructure, microhardness and corrosion behavior of Ni-Ti coatings were investigated. The results showed that a pyramidal surface structure evolved into a spherical surface structure of the coatings with increasing Ti nanoparticle loading. The content of Ti in the Ni-Ti coatings first increased and reached the maximum value of 7.1 vol.% at the loading of 16 g/L, then decreased due to agglomeration of nanoparticles. The [200] preferred orientation gradually evolved to [111] orientation with increasing Ti nanoparticle loading. At Ti nanoparticle loading of 16 g/L, the minimum crystallite size (44 nm) and maximum microstrain (0.25%) were obtained. The microhardness of the Ni-Ti coatings was improved and obtained the maximum value at the loading of 16 g/L, The anti-corrosion behavior of the Ni-Ti coatings had increased trend with increasing Ti nanoparticle loading. The pitting corrosion and the selective dissolution of Ti nanoparticles happened in corrosion of Ni-Ti coating electrodeposited at the loading of 16 g/L in a 3.5 wt.% NaCl solution.