Quantitative measures of corrosion and prevention: application to corrosion in agriculture

The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in The Netherlands is considered in detail. Attention is paid to relations between c.p.f. and c.c., the corrosion costs, possible cost savings and the applied corrosion protection scheme on farms. It is shown that the c.p.f. and the c.c. are useful expedients in a preliminary analysis of corrosion costs and possible cost savings on farms in relation to the corrosion protection methods applied.\ud \ud It is concluded that significant cost savings on arable farms can be derived by improving corrosion protection. No statistically significant cost savings are possible by improving corrosion protection on the dairy farms considered in this research

Development of new processes to protect zinc against corrosion, suitable for on-site use

Protection against corrosion of metals is well known as an important issue in numerous fields. In all cases, the improvement of durability of these metals has to be connected to the development of environmentally friendly processes. Sol–gel protective coatings have shown excellent chemical stability and enhanced corrosion resistance for zinc substrates. Further, the sol–gel method, used as technique of surface protection, showed the potential for the replacement of toxic pre-treatments. This paper highlights the recent developments and applications of silane based sol–gel coatings on zinc substrates. Then, the challenges for industrial transfer of the developed process are also discussed because this process presents a disadvantage for on-site use, which is the too time-consuming thermal treatment. So, the goal of this study was to determine the convenient experimental conditions to reduce the duration of heat treatment of the hybrid sol–gel layer, compatible with the severe industrial requirements, without reducing the protection against corrosion. To reach this objective, a correlation between the results of chemical analyses and the protection against corrosion efficiency was established

Galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718 and graphite-epoxy composite material: Corrosion occurrence and prevention

The effects of galvanic coupling between D6AC steel, 6061-T6 aluminum, Inconel 718, and graphite-epoxy composite material (G/E) in 3.5% NaCl were studied. Measurements of corrosion potentials, galvanic currents and corrosion rates of the bare metals using weight-loss methods served to establish the need for corrosion protection in cases where D6AC steel and 6061-T6 aluminum are galvanically coupled to G/E in salt water while Inconel 718 was shown to be compatible with G/E. Six tests were made to study corrosion protective methods for eliminating galvanic corrosion in the cases of D6AC steel and 6061-T6 aluminum coupled to G/E. These results indicate that, when the G/E is completely coated with paint or a paint/polyurethane resin combination, satisfactory protection of the D6AC steel is achieved with either a coat of zinc-rich primer or a primer/topcoat combination. Likewise, satisfactory corrosion protection of the aluminum is achieved by coating it with an epoxy coating system

Electrochemical corrosion studies

The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel

Analysis of stray current induced by cathodic protection on steel-framed masonry structures

Cathodic protection (CP) has been successfully employed to protect steel-framed masonry buildings from corrosion related damage. When a CP system is installed to protect the structural members, other metallic items which are within the fabric of the structure but are not in direct electrical continuity may suffer from stray current interactions, resulting in accelerated corrosion of the discontinuous items. Therefore, these must be considered when CP systems are designed prior to installation. This paper presents both experimental and numerical studies into the risk and extent of stray current corrosion in steel-framed masonry structures when subject to impressed current cathodic protection. The objective is to allow CP systems to be optimised so that interference is minimised without compromising the technical or cost benefits of this method of corrosion control

The properties of protective oxide scales containing cerium on alloy 800H in oxidizing and oxidizing/sulphidizing environments

The corrosion protection of oxide scales formed by electrophoretic deposition in a cerium-containing sol on Alloy 800H, a 32Ni-20Cr steel, followed by firing in air at 1123 K was studied in oxidizing and mixed oxidizing/sulphidizing environments at elevated temperatures. In particular, the influence of type of sol solvent, sol concentration, and thickness of deposited layer on the protection were studied. An optimized treatment was deduced which led to a significant improvement in corrosion behavior in oxidizing/sulphidizing environments.\u

Erosion-corrosion behaviour of Zirconia WC-6Co, WC-6Ni and SS316

The current study investigates a ceramic, two cermets and a metal under solid-liquid impingement with 3.5% NaCl and 150mg/l hydraulic fracturing sand at two extreme angles of impact, 90° and 20°. The materials tested were Zirconia, sintered WC-6Co, sintered WC-6Ni and SS316. Each material was exposed to a testing regime using re-circulating impinging jet apparatus with a velocity of 19m/s and one hour duration. The electrochemical properties of the materials were investigated in-situ through anodic and cathodic polarisation and application of cathodic protection. Post experimental analysis of the degraded surface was completed using Scanning Electron Microscopy (SEM) and Optical 3D Imaging. Zirconia exhibited a brittle response to erosion-corrosion testing with the mass loss at 90° being fifty times greater than the negligible mass loss at 20°. WC-6Co and WC-6Ni both outperformed SS316 under all solid-liquid impingement erosion-corrosion testing regimes. WC-6Ni exhibited slightly better erosion-corrosion resistance over WC-6Co at both 90° and 20°. SS316 had the best corrosion resistance and showed passivation during anodic polarisations in solid-liquid impingement conditions. The nickel binder increased the corrosion resistance of WC-6Ni over WC-6Co. Cathodic protection was successfully applied on sintered WC-6Co and SS316 isolating the key components of erosion-corrosion