Induction periods during anodic polarization of zinc in aqueous oxalic acid solutions

Influence of the Anodization Process on Zamak 5 Corrosion Resistance

“…Already the 451.50 cm -1 peak corresponds to ZnO 12 and the 490 cm -1 peak to the Zn-O and C-C 13 vibrational bands. Therefore, it is observed that anodizing in zamak 5 forms zinc oxalate and zinc oxide in agreement with results observed by Lilov et al 9 . On the other hand, as zamak 5 contains 4% Al in its chemical composition, which is presented as solute in zinc solid solution (β) and eutectic with two phases (β + α'), it is assumed that the observed bands may also be associated with aluminum oxalate or aluminum oxide.…”

“…The ATR-FTIR spectrum, Figure 2, of the anodized zamak 5 sample shows bands between 4000-400 cm -1 similar to those found by Lilov et al 9 , which used a typical spectrum of zinc oxalate dihydrate (ZnC 2 O 4 .2H 2 O). Bands in the 4000-600 cm -1 region of the anodized sample (Figure 2) should be assigned to: In accordance with previous studies on hydrated metal oxalates 9 , a band for the bending O-H mode of water was not observed due to the overlapping with the strong IR band of the asymmetric C-O stretching vibrations at 1620 cm -1 . In addition, bands were identified at 611.65 and 490.46 cm -1 for anodized zamak 5 (Zatv-30-G), Figure 2, which corresponds to the range between bands (600-500 cm -1 ) providing information on the chemical bond between Zn and O 11,12 .…”

“…Figure 4 shows a surface containing crystallites, more clustered than those identified by Lilov et al 9 , and cracks.…”

“…At the beginning of anodization (1-a), a potential transient delay occurs which, according to Lilov et al 9 , was related to the induction period, with the formation of zinc crystals on the metal surface as a function of contact with the electrolyte. The induction period observed in this study was approximately 10 seconds using 300 mol.m -3 oxalic acid, in agreement with the results of Lilov et al 9 .…”

Electrochemical Obtaining and Corrosion Behavior of Zinc-Polyaniline (Zn-PANI) Hybrid Coatings

“…This mechanism is clearly illustrated by Wessling [30][31][32], Schauer et al [33], Sathiyanarayanan et al [34], and Nguyen et al [35]. Some other suggestions about the corrosion protection improvement of Zn-based functional layers have been elaborated in [36].…”