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The purpose of this paper is to study the susceptibility of these three commonly used corrosion resistance fasteners in seawater. For a more practical scenario, a local Atlantic coastal seawater as received was used.

Carbon fiber reinforced polymer (CFRP) was fabricated with T700 carbon fiber (Toray Inc.) and VE8084 vinyl ester resin (Ashland) to make a unidirectional composite panel of thickness 1.8 mm. A conductive paint was applied to one of the sample edges that was perpendicular to the fiber direction, providing an electrical contact with carbon fibers to connect a copper wire. This external electric connection was used for potential measurements of both the open circuit potential (OCP) of the CFRP sample, and the mixed potential of the fastened set: consisting of the CFRP and the metallic fastener fastened to it. Three common fastener alloys were selected: 316SS, Monel and Titanium. For this purpose, a high impedance voltmeter was used in conjunction with a saturated calomel reference electrode. Measurements were taken daily. For longer time measurements, a four-channel high impedance analog data logger was used with 30 min sampling rate.

For both 316SS and Monel fastened sets, crevice corrosion occurred inside the occluded regions of the set, when immersed in coastal seawater. The attack was more severe for 316 stainless steel set. An isolated island attack of faceted surfaces morphology was seen for 316SS set. While, a circular ring of preferential grain boundary attack appeared for Monel set, indicating an IR (voltage) drop mechanism is more likely operating. Titanium-fastened sets showed high resistance to crevice corrosion when simmered in seawater. However, for long-time exposure, the sets became more susceptible to crevice corrosion attack supported by CFRP attachment (oxygen reduction reaction taking place at the carbon fibers).

Evidently, titanium, stainless steels and Monel are good candidates for galvanic corrosion resistance. However, their susceptibility to crevice corrosion when coupled with CFRP is a new challenging topic that needs further investigation. This is very important today because the vast application witnessed for CFRP material. This work involves developing an original methodology for this kind of investigation and was done at advanced laboratories of SeaTech at Florida Atlantic University by the Atlantic coastline.

ANY discussion of high‐performance fasteners must first define the term because the requirements for “high performance” can vary with the application.

The purpose of this paper is to examine the performance of a fastener composite coating system, sherardized (SD) coating/zinc-aluminum (ZA) coating whether it has good performance in marine environment.

In this paper, SD coating was fabricated on fastener surface by solid-diffusion method. ZA coating was fabricated by thermal sintering method. Corrosion behaviours of the composite coating were investigated with potentiodynamic polarization curves, open circuit potential and electrochemical impedance spectroscopy methods.

Neutral salt spray (NSS) and deep sea exposure tests revealed that the composite coating had excellent corrosion resistance. Polarization curve tests showed that corrosion current density of the sample with composite coating was significantly decreased, indicating an effective corrosion protection of the composite coating. OCP measurement of the sample in NaCl solution demonstrated that the composite coating had the best cathodic protection effect. The good corrosion resistance of the composite coating was obtained by the synergy of SD and ZA coating.

SD/ZA coating can be used in marine environment to prolong the life of carbon steel fastener.

SD/ZA composite coating can reduce the risk and accident caused by failed fastener, avoid huge economic losses.

A new kind of composite coating was explored to protect the carbon steel fastener in marine environment. And the composite coating has the long-term anti-corrosion performance both in simulated and marine environment test.

The Fasteners Corrosion Laboratory, opened last month in Birmingham, is run by Frederick Mountford (Birmingham) Ltd. and Ionic Plating Ltd. Its primary concern will be with the wide variety of corrosion problems encountered in the many industries served by the group. It is the only corrosion laboratory concerned with this aspect of industry.

The total life and reliability of a fastened joint does not depend entirely upon the initial strength of the components involved but also upon the compatibility of the materials concerned with the service environment.

SURFACE treatment alternatives to traditional zinc and cadmium plating are in demand to ensure components meet extended corrosion guarantees and to overcome the toxic hazards of electroplating techniques. Matrix fluorocarbons provide these alternatives and this article describes how they meet the often conflicting demands for corrosion protection, thread lubrication, fine tolerance and the avoidance of hydrogen embrittlement.

This study aims to investigate the effect of post-treatment on anti-corrosion performance of Al coating on the surface of Ti-6Al-4V (TC4) fastener.

The Al coatings with different layer structures were prepared on TC4 by middle-frequency and direct-current combined magnetron sputtering. The cross-sectional morphology and surface roughness of coatings were characterized by scanning electron microscope and atomic force microscope. The corrosion resistance was evaluated by electrochemical method. The monolayer coating was post-treated by Alodine chemical conversion, Ar⁺ bombardment and a combination of two methods above.

The results show that the interfaces in bilayer and trilayer coatings reduce the defects. Ar⁺ bombardment reduces the corrosion current density, and Alodine chemical conversion leads to a higher pitting corrosion potential. The combined post-treatment has the highest polarization resistance.

The corrosion resistance of the Al coating is enhanced as the layer quantity increases. The combination of two post-treatments, Ar⁺ bombardment and Alodine chemical conversion, could achieve an overall improvement in corrosion resistance of Al coating.

Enviromaster fluoropolymer coated engineering fasteners are so resistant to corrosion that even after prolonged exposure to hostile environments such as those surrounding chemical plants, oil rigs, marine installations etc., they can be removed easily using conventional tools, according to Charles Richards Fasteners Ltd., P.O. Box 23, Heath Read, Darlaston, West Midlands.

SAFETY is uppermost in the minds of all who travel by sea, and the use of reliable materials and methods of boat construction is essential in establishing confidence. The use of fasteners which can perform their function without seizing or deterioration by corrosion over long periods of service goes a long way towards obtaining the desired standard of performance.

HIGH efficiency is essential in aircraft structures and corrosion protection is critical. Whether the corrosion is readily apparent or of a kind that degrades the mechanical properties of a joint, for example, without much visible evidence, serious reductions in static or fatigue strength can result. Because of the widely different climatic conditions in which aircraft operate, the rate of corrosion varies considerably. It can only take place where water either as a liquid or water vapour in air of high humidity, is present. A metal will not corrode if it is completely dry.