Introduction of Heavy Micro‐Titanium‐Carbide Particles into Zn–Ni Coatings on Steel During In Situ Brush Electroplating

Abstract

The heavy micro titanium carbide (TiC) particles were first introduced into brush electroplated Zn‐Ni coating (TiC‐0 coating) by using some surfactants here. The effect of TiC concentration of brush electroplating solution on the properties of Zn‐Ni‐TiC coatings was investigated. It was found that the coating hardness and corrosion resistance were enhanced significantly due to the co‐deposition of TiC and an optimal coating with a thickness of 71 μm and adhesive strength of 37.2 MPa was obtained when TiC concentration was 40 (g/L) (TiC‐40 coating). The pencil hardness of TiC‐0 and TiC‐40 were 2H and 5H, respectively. The corrosion resistance time to hot NH4NO3 solution (or inferred neutral salt spray) of TiC‐0 and TiC‐40 were 40 min and 240 min (or 321h and 1995h), respectively. Many pores appeared on the coating due to the incomplete overlap of many batch layers. The TiC content was the factor dominating the coating hardness and corrosion resistance by changing the structure, contact angle and pore diameter of coating, thereby changing the linear polar resistance Rp from potentiodynamic polarization curves, charge transfer resistance Rct or |Z|0.01Hz or polarization resistance from EIS. The content of Zn‐Ni alloy was the factor dominating the adhesive strength of Zn‐Ni‐TiC coating.This article is protected by copyright. All rights reserved.