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The purpose of this paper was the investigation of corrosion behaviour of Ni-6Al-10Cu-11Fe-15Cr alloy, as a candidate material for inert anodes in aluminium electrolysis industries.

The samples were prepared by casting, and then were oxidized at 1,000°C for 30, 70 and 100 hours, respectively. To determine corrosion resistant of the samples, they were exposed to molten cryolite at 930°C for 70 hours. Then the surface layers were studied.

Results showed that by extension of corrosion time, thickness of oxide layers increases. In addition, it was found that Al2O3 and Cr2O3 are the major oxide compounds that appear on the surface of the sample.

In this paper, the Ni-6Al-10Cu-11Fe-15Cr nickel base alloy has been selected to study its corrosion behaviour in molten cryolite as a candidate for inert anodes. It was found out that by addition Al and Cr into the alloy composition, due to formation of Al2O3 and Cr2O3 following oxidation, the substrate was protected from corrosion attacks.

The increasing use of platinum — containing anodes in cathodic protection and the discussions which took place at the recent International Congress on Metallic Corrosion in London, make this subject of topical interest. In this review paper the author provides a balanced overall picture of the various applications in this field. The development, advantages and limitations are described of three types of support for a thin layer of the metal, as well as an alternative use of platinum in the platinum‐lead bi‐electrode. At present only two types of platinum electrode can be widely recommended.

How many individuals and organisations are normally involved in the protection from corrosion of any one buried structure such as a welded steel pipeline? Following completion of construction and in the early years of service how divided is the responsibility for the integrity of the corrosion prevention system? The importance of these questions will of course vary according to such factors as safety in the case of a high pressure gas line or one carrying toxic products, to the expense of repairs and the overall cost and implications of downtime.

The purpose of this paper is to consider the use and application of the “grey system” modelling methodology for the prediction and characterisation of inert anodes used in the aluminium electrolysis industry.

Cermet was very interesting potential material for developing inert anodes, which was composed of ceramic phase (NiFe₂O₄) and metal/alloy phase (nickel‐iron‐copper).

Differential thermal analysis showed that newly fabricated cermet had good performance. The calcination temperature was very important for evaluating material properties, so was obtained in order to build the forecast grey model.

Through calculation the GM(1,1) model was proved to be accurate in predicting technical parameters, and able to pinpoint precisely the properties of cermet materials.

Last month the author discussed platinum anodes using inert supports such as plastic and ceramic, common metal supports such as copper, and supports with passivating metal such as titanium or platinum. This concluding section discusses applications and operation. It is concluded that only two types of supported platinum electrode can be recommended at present—a platinum‐palladium foil anode with a plastic mount and platinised titanium.

Recent developments in marine cathodic protection have produced automatic static, solid‐state polarisation control systems. Methods are now available capable of providing complete and continuous protection of all under‐water portions of a ship's hull under any conditions. This evaluation is by a U.S. Navy engineer responsible for initiating many repairs attributable to electrolysis damage.

During a two‐week voyage of the S.S. Israel from Haifa to New York, experiments were conducted with a platinum‐clad trailing anode system for cathodic protection. Preparation for the voyage and day‐to‐day working of the experiments are described as are the successful efforts made to overcome the mechanical difficulties that arose. Concrete results that emerge indicate a growing and glowing future for such installations on large ships.

THE APPLICATION of cathodic protection to marine structures, using both galvanic and impressed current systems, is a well‐established technique for reducing or preventing corrosion. It has been shown, for example, that a galvanic system applied to US Navy destroyers reduced maintenance costs by $10,000– $20,000 per ship per overhaul, and it is likely that impressed current systems will effect greater savings. Lead alloy anodes, or lead‐platinum bi‐electrodes, are being increasingly used for marine cathodic protection systems since they not only have a greater robustness than platinum or graphite anodes (and a greater coulometric efficiency than graphite) as well as lower consumption rates. The long life and ease of installation of lead alloy anodes, together with their high current carrying capacity, are strong reasons for their use.

As shipowners and shiprepairers will certainly be aware, costs of steel repairs resulting from corrosion, particularly in older and more vulnerable vessels such as tankers and bulk carriers are a significant proportion of the total maintenance expenditure. The economic problems of the industry in recent years have inevitably led to economies in maintenance budgets and, now the market has improved, the corrosion problems which have accumulated will have to be dealt with. In general, the two major techniques for corrosion protection, coatings and cathodic protection are complementary to one another and neither, on its own, can provide the complete answer.