Study On Performance Of Sealing Plasma-Sprayed Nano-TiN Coatings

The electrochemical corrosion property of plasma sprayed nano-TiN coatings whichwere sealed with stearic acid were studied by measuring the curves of potential-time,polarization and EIS. The wearing property and tissue topography immersed in the seawater for along time were researched, while the corrosion resistance mechanism was analyzed byelectrochemical corrosion theory to established micro-corrosion model. The conclusion wassummarized as follows:(1) Nano-TiN coatings were sealed with different sealant and the electrochemicalcorrosion property was analyzed. The results were showed that stearic acid had the bestsealing effect compared with other sealant.(2) The best sealing technology was optimized by orthogonal test, and EIS curves of thenano-TiN coatings which were sealed with optimal technology showed that Warburgimpedance characteristic and capacitance arc were presented in early/medium-termcorrosion. Two time-constants of the curves which were presented after immersing for 408hshowed that corrosion process was up to the medium-term and the corrosive liquid seepagewas impeded.(3) The antifriction and the anticorrosion of the nano-TiN coatings which were sealedwith stearic acid were enhanced by doing the abrasion test. Wearing loss and frictioncoefficient decreased obviously, especially the friction coefficient of nano-TiN coatingswhich were sealed with stearic acid was the same as 2/3 of the friction coefficient ofnano-TiN coatings.(4) The results, analyzed from the macrocorrosion experiment of nano-TiN coatings,showed that nano-TiN coatings were stable and had no reaction in the process of boiling.Iron oxide was found in the surface of nano-TiN coatings and nothing in the surface ofnano-TiN coatings which were sealed with stearic acid, only some element of Fe weredetected in the interface of coating/substrate, which proved that the corrosion resistancewas enhanced. The innovation was the research of corrosion process and mechanism by combiningmacrocorrosion with microcorrosion.