Corrosion protection performance

Salt spray test. The model coatings of Table I are of the high solid type used in automotive top coats. Their primary function is not corrosion protection since this is first of all a matter of phosphate layer, electrocoat and/or primer. However, the topcoats may contribute to corrosion protection by their barrier function for water, oxygen and salts. Therefore their permeability is important as one of the factors in the corrosion protection by the total coating system. We feel that a salt spray test of the model coatings directly applied to a steel surface is of little relevance for their corrosion protection performance in a real system. 

Ohmic contacts that stand corrosive environments at high temperatures are still to be fully developed, for a review, see [121], It has been shown that TiW contacts covered by TaSi + Pt as corrosion protection performed better at high temperature in an environment of pulses than standard alloyed Ni contacts, also with... 

Electrochemical impedance spectroscopy (EIS) is a valuable method with which to study the barrier property and corrosion protection performance of polymer-coated metals it has been widely used in this field in recent years [11-15]. Many examples can be found in the literature, which illustrate the performance deterioration of different coatings on metals as well as pretreatment effects on the properties of... 

The overall corrosion protection of a metal, as well as general protective coatings irrespective of their function of coating, depends on the performance of a system as a whole, including its many interfaces and coating layers. These factors are not only mutually dependent as a combination but also in the order of application (permutation). Any single factor cannot be treated as a dominant one. There is very little work in the literature that focuses on the role of interfacial factors in the corrosion protection performance of coated systems. 

An ideal model system was selected to study the interfacial factors with EIS [19]. The model system was Parylene C-coated Alclad (aluminum-clad aluminum alloy). In this system, the surface state of the top surface (salt solution/coating interface) and the adhesion of the coating (coating/metal interface) were modified to study the influence of these factors on the corrosion protection performance of the system. 

E-coat stripping. Both plasma-treated panels show excellent corrosion protection performance as compared to the control panels. All [2A] panels with different plasma treatments and plasma polymer coatings, which were corrosion tested in both SO2 and Prohesion salt spray tests, were similarly scanned, and the corrosion width was evaluated by using a scanned image and computer calculation of the corroded area. Figure 31.19 compares the corrosion width obtained by the two methods. 

It should be emphasized that the primers in the plasma coating systems applied to the IVD Al-coated A1 alloys could not be removed by the commercial Turco paint stripper solution. This tenacious and water-insensitive adhesion at the primer/IVD interface achieved by TMS cathodic polymerization in a closed reactor system must be responsible for the excellent corrosion protection performance of these plasma coating systems. In other words, excellent corrosion protection of IVD Al-coated A1 alloys can be accomplished with chromate-free primer coatings with the aid of tenacious and water-insensitive interface adhesion. 

This paper wiU build on previous reviews which have sought to explore the marmer in which surface analysis methods can be purposefully employed to understand adhesion phenomena [4—6], with an emphasis on the elucidation of interphase chemistry. The rationale behind such an approach is that it is this critical region of a polymer/metal or polymer/polymer couple that will influence the performance of the overall system, be it the durability of an adhesive joint or the corrosion protection performance of an organic coating. 

The corrosion protection performance of the sol-gel films was estimated by accelerated test using immersion in a NaCl solution. Fig. 2 demonstrates the coated surface after the immersion tests. The reference sample prepared without titania nanoparticles is strongly attacked after 10 days in 0.05 M NaCl. In contrast, the sample with titania nanoparticles seems almost untouched even after one month in concentrated NaCl solution. 

U. Riaz, S. Ahmad, and S. M. Ashraf, Comparison of corrosion protective performance of nanostructured polyaniline and poly(l-naphthylamine)-based alkyd coatings on mild steel. Mater. Corn, 60, 280-286 (2009). 

Kobayashi, K., Lizuka, T., Kurachi, H. and Rokugo, K. (2010). Corrosion protection performance of high performance fiber reinforced cement composites as a repair material. Cement and Concrete Composites, 32 411 20. 

FIGURE 14.5 (See color insert.) Corrosion rate of MO-PANI/COPU and CSA-PNA/LOPU composite coatings in (a) 5% HCl, (b) 5% NaOH, and (c) 3.5% NaCl. (Reprinted from Prog. Org. Coat., 65, Riaz, U. et al. Effect of Dopant on the Corrosion Protective Performance of Environmentally Benign Nanostructured Conducting Composite Coatings, 405, Copyright 2009, with permission from Elsevier.)... 

Zheludkevich, ML, Serra, R, Montemor, MF, Yasakau, KA, Salvado, IMM, Ferreira, MGS. 2005. Nano structured Sol-Gel Coatings Doped with Cerium Nitrate as Pretreatments for AA2024-T3— Corrosion Protection Performance. Electrochim. Acta, 51, 208. 

Riaz, U, Ahmad, SA, Ashraf, SM, Ahmad, S. 2009. Effect of Dopant on the Corrosion Protective Performance of Environmentally Benign Nanostmctured Conducting Composite Coatings. Prog. Org. Coat., 65, 405. 

Patil, S., S.R. Sainkar, and P.P. Patil. 2004. Poly(o-anisidine) coatings on copper Synthesis, characterization, and evaluation of corrosion protection performance. Appl Surf Sci 225 (1-4) 204. 

The results were positive and promising. Bagherzadeh et al. [81] found that the anticorrosion performance of a two-component water-based epoxy resin coating system was improved by adding only 0.02 wt% nano-PANI. Ahmad et al. [82] investigated the corrosion protection behavior of waterborne resorcinol formaldehyde (RF)-cured composite coatings of poly(l-naphthylamine) (PNA)/poly(vinyl alcohol) (PVA) on mild steel, and even superior corrosion protective performance was observed in different corrosive media when compared with the reported solvent-based conductive polymer coatings. 

Riaz, U., Ahmad, S.A., Ashraf, S.M., and Ahmad, S. (2009) Effect of dopant on the corrosion protective performance of environmentally benign nanostructured conducting composite coatings. Prog. 

Evaluation and Testing. There is no laboratory test available to predict corrosion protection performance of a new coating system. Suppliers and end users of coatings for such applications as bridges, ships, chemical plants, and automobiles have collected data correlating performance of different systems over many years. These data provide a basis for selection of current coatings... 

N. Pirhady Tavandashti, S. Sanjabi, and T. Shahrabi, Evolution of corrosion protection performance of hybrid silica based sol-gel nanocoatings by doping inorganic inhibitor, Materials and Corrosion, vol. 62, no. 5, pp. 411-415, 2011. 

Hamdy, A. S. Beccaria, A. M. Traverse, P. (2005). Effect of surface preparation prior to cerium pre-treatment on the corrosion protection performance of aluminum composites. Journal of Applied Electrochemistry, Vol. 35, No. 5, pp. 473-478, ISSN... 

W. Funke, H. Haagen, Empirical or Scientific Approach to Evaluate the Corrosion Protective Performance of Organic Coatings, Ind. Eng. Chem. 17 (1978). 

The results obtained by both Mansfeld et al. and Hinton et al. are encouraging and suggest that a conversion coating based on a Ce oxide could be an attractive alternative to the chromate conversion coatings widely used to protect aluminium and zinc. However, as a practical commercial process, treatment times would need to be of the order of minutes, and the corrosion protection performance would need to be similar to that provided by the chromate conversion coating. 

An anodized coating/film can be characterized by its thickness, composition and microstmcture. These parameters are important to its corrosion protection performance. 

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