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Sprayed metal coatings are an alternative means of effectively protecting steel structures and equipment exposed to severe environments where other coatings, such as paint, are unsuitable or provide only temporary protection. Selecting the most suitable material for a given application is a very important step in achieving success. For resistance to corrosive environments, zinc and aluminium are the most successful and widely used coatings, both being anodic to iron and steel. The performance of sprayed metal coatings is a function of the environment, coating thickness, adhesion, density and the type of sealer used. The mechanism of adhesion is mainly mechanical, the bond strength being dependent on the application process chosen and standard of surface preparation. This paper describes the results of research work associated with hot sprayed aluminium applied by combustion flame and electric arc processes using compressed air and argon carrier gases. Studies included ductility and adhesion tests, scanning electron microscopy of surfaces and cross sections, and Auger surface analyses.

Stress corrosion cracking at the weld areas in the interior of blast furnace stoves has become a world wide problem which has been accentuated by the higher operating temperatures and pressures now used. This paper describes the work carried out to evaluate various protective coatings proposed for application to the interior of the stove shell plates to prevent the stress corrosion. A heat and chemical resistant polyurethane primer‐pitch polyurethane top coat has given superior results to all coatings tested, particularly when applied over a hot sprayed ceramic.

For any paint or coating system performance in service is determined by the whole formulation, with each of the individual ingredients contributing either directly or by interaction to the overall balance of film properties. Within these constraints, paint formulators recognise that certain materials have a well defined role to play and in many instances a consideration of a coatings service requirements does largely dictate the initial approach to formulation. One such ‘key’ group of materials are the pigments added to anticorrosive paints to provide protection to metallic substrates under aggressive conditions of exposure. One group of these pigments inhibit corrosion by perturbing in one of a number of ways the chemical reactions that would otherwise occur on the substrate surface in the presence of water. Other types of protective pigments function by improving the barrier properties of the applied paint film so that water cannot readily permeate through and initiate corrosion reactions on the substrate. Pigments in this group typically have a flake‐like particle shape which enables a ‘leafing’ effect to be achieved within the liquid coating after application. The inhibitive types of pigment need to be in close proximity to the substrate to function properly, and accordingly these are normally placed in primer coats only. The flake pigments which reduce moisture permeation through the film are most effective if added in depth, and these are often added to severa or all of the coats comprising a system, or are included as the sole protective pigment in high‐build paints. Recent developments in both of these broad groups of inhibitive and flake pigments will be considered in this article.

If a weather‐beaten structural steelwork, protected by a full system of anticorrosive coatings, will show a lifetime of over 20 years without any maintenance during this time, we will speak of a ‘longterm Corrosion Protection.’ These 20 years often seem to be too long, but many case‐histories of structural steelworks over the whole of Europe, such as bridges, tankfarms, cranes etc. will prove it. By the way, the German Railway Administration foresees a major repainting of their objects only every 20 years, the Swiss Federal Railway Administration only after 25–30 years. The most parts of these protective coatings are pigmented with Micaceous Iron Oxide (MIO), a pigment with the highest life expectance.

Micaceous iron oxide (MIO) paints are employed throughout the world to provide long‐life corrosion protection for structural steelwork.

Lamellar micaceous iron oxide paints are successfully employed to provide longlife corrosion protection for metallic structures when exposed to highly aggressive environments. The aim of this work was to formulate and manufacture lamellar micaceous iron oxide paints, able to be used on the protection of steel structures exposed to water. Several formulation and manufacture variables were taken into account. Many paint films fail when they are saturated with moisture and blistering is a common failure because primers usually are not designed to allow the liquid to dissipate back out through the film. Consequently the film can not resist the formation of projections which result in local adhesion loss. For maximum durability, primers must be properly formulated and manufactured. Film permeability, which depends on paint composition (pigment volume concentration) and micaceous iron oxide dispersion time, seems to be the key characteristic controlling subsequent coating performance. Laboratory results indicated that lamellar micaceous iron oxide is a pigment which provides an anticorrosive action by providing a barrier effect. Film permeability must be compatible so as to attain a satisfactory rusting and blistering resistance.

Studies the effects of non‐isometric pigments on the anticorrosion properties of coating films. The optimum concentrations for using iron mica, muscovite, and graphite have been determined. The results obtained on using the natural iron mica are compared to those obtained with a synthetic product. As binders for the coatings epoxy resin, polyurethane and alkyd resins were used. The results allow the conclusion that on the pigmentation with iron mica the protection function of top coatings against the corrosive media can be considerably increased.

The paper deals with using lamellar pigments for anticorrosive barrier coatings. By depositing a ferric oxide layer on a muscovite particle a pigment is obtained, which being applied to coatings improves the mechanical properties thereof, resistance to UV radiation and acts as an anticorrosion barrier. The optimum concentration of lamellar surface‐treated muscovite in the coatings amounts to 20 vol. %.