Electrodepositvely Introducing Micro Particles of TiO2 in Ni–B Coatings and Its Effect on Physical Properties and Corrosion Performance of NiB Coatings

Abstract: This study focuses on understanding the effect of TiO<inf>2</inf> micro particle introduction on surface morphology, structure, thermal stability, mechanical properties, and corrosion performance of NiB coatings. The surface morphology is observed to become rough and irregular by the addition of the TiO<inf>2</inf> microparticles. However, TiO<inf>2</inf> micro particle inserted NiO coating (NiB@TiO<inf>2</inf>) retained the clusters of grains type morphology as that of NiB coating. The crystallinity of NiB coating increased by addition of TiO<inf>2</inf> particles and no significant changes in the thermal behavior of the Ni~B coating is observed by the formation of NiB@TiO<inf>2</inf> composite. Upon addition of TiO<inf>2</inf> the mechanical properties Ni~B composite such as nano hardness and elastic modulus and corrosion potential improved. The improvement in hardness, elastic modulus was clearly due to addition of the harder and stiffer TiO<inf>2</inf> particles which caused Orowan strengthening while the improved corrosion performance was attributed to the reduction in significant number of active corrosion sites brought about by the introduction of inert TiO<inf>2</inf> particles.