Effect of cerium on the physicochemical and anticorrosive features of TEOS-GPTMS sol-gel coatings deposited on the AZ31 magnesium alloy

Cerium conversion coating and sol-gel coating for corrosion protection of the WE43 Mg alloy

“…3) [43,92], supporting the proposed physical model, at which the hybrid coating capacity (C H ) is represented as dotted lines, indicating that, even though presented at the metal surface, as proved by EDS analyses, it cannot be detected by the EIS measurements. On the other hand, for the sample pro- tected only with the Ce conversion coating, the cracked nature of this layer, associated with its low hydrophobicity [63,70,92] (Fig. 4b), would lead only to a slight increase in the corrosion resistance, as verified in the experimental results.…”

“…The resistance associated with the HF capacitive loop, Rct, for all samples, initially increases (up to 18 h), which might reflect the precipitation of protective corrosion products. However, comparing the samples without (WE43-T5 and CeP) and with the hybrid coating (Hyb and CeP-Hyb), Rct for these two latter samples are roughly four times higher, indicating the precipitation of corrosion products with better barrier properties, as suggested by Hernández-Barrios et al [92], and/or the reduction of the exposed area of unprotected Mg due to the presence of the hybrid coating.…”

“…Regarding the variation of this parameter, it remains practically constant for the bare WE43-T5 sample and is slightly higher and with an increasing tendency for the CeP sample. This is likely due to the hydrophilic nature of the Ce precipitate [63,70,92], contributing to increased interaction with water molecules (see also results of the contact angle measurements Fig. 4b).…”

“…It is important to emphasize that the order of magnitude of the CPE determined for the HF capacitive loop for the Hyb and CeP-Hyb coatings (10 -6 F.cm -2 .s (n-1) ) is not compatible with a thick protective layer, usually in the order of few micrometers, determined for sol-gel coatings (Fig. 3) [43,92], supporting the proposed physical model, at which the hybrid coating capacity (C H ) is represented as dotted lines, indicating that, even though presented at the metal surface, as proved by EDS analyses, it cannot be detected by the EIS measurements. On the other hand, for the sample pro- tected only with the Ce conversion coating, the cracked nature of this layer, associated with its low hydrophobicity [63,70,92] (Fig.…”

Tannin from Schinopsis balansae applied to the nanofunctionalization of protective antifungal coatings

“…The solgel process involves the transition of a system from liquid phase (sol) to solid phase (gel) through chemical reactions of hydrolysis and condensation of the precursors [18]. The sol-gel method affords various merits as follows: reliability of the consuming equipment, simple fabrication environment, high uniformity on the thin films and utilization of different sizes with substrate combinations [19,20]. It has previously been observed that sol-gel coating added with biocides was used to control the biodeterioration of bricks [21].…”