Protective Characteristics of TiO2 Sol-Gel Layer Deposited on Zn-Ni or Zn-Co Substrates

This study aimed to present the differences in corrosion properties and protective ability of two bi-layer systems obtained on low-carbon steel a model corrosive medium 5% NaCl solution. These newly developed consist Zn-Co (3 wt.%) or Zn-Ni (10 alloy coatings as under-layers very thin TiO2 sol-gel film top-layer. Scanning electron microscopy (SEM) is used for characterization surface morphology samples indicating that some quantitative appear result different composition both zinc alloys. Surface topography investigated by means atomic force (AFM), hydrophobic are studied contact angle (CA) measurements. investigations demonstrate sample types possess grain nanometric decreases slightly. X-ray diffraction (XRD) photoelectron spectroscopy (XPS) chemical electronic structure samples. The roughness Rq Zn-Ni/TiO2 49.5 nm, while Zn-Co/TiO2, value 53.4 nm. water angels 93.2 95.5 Zn-Co/TiO2 systems, respectively. also show co-deposition Zn Ni forms coating consisting entirely Ni2Zn11, other contains Zn, Co intermetallic compound CoZn13. resistance estimated potentiodynamic polarization (PDP) curves, well (Rp) measurements prolonged test period (35 days). results compared with characteristics ordinary an equal thickness. experimental data presents positive influence enhanced environment causing localized corrosion—lower current density about one magnitude order (~10−6 A.cm−2 ~10−5 Zn) after 35 days (~10,000–17,000 ohms ~900 Zn).