Metals industry graphitic corrosion

Because of the considerable corrosivity of chlorine toward most metals, anodic chlorine evolution can only be realized for a few electrode materials. In industry, graphite had been used primarily for this purposes in the past. Some oxide materials, manganese dioxide for instance, are stable as well. At present the titanium-ruthenium oxide anodes (DSA see Chapter 28) are commonly used. 

Recently conductive polymer materials (CPM) have obtained a wide usage in different branches of industry. It takes place due to combination of performance characteristics, availability and low cost. Conductive polymer materials have conductivity specific to metals, and such advantages of the plastics as corrosive resistance, high processing quality, low density, and elasticity. Nowadays the most perspective method of conductive polymer compositions generation is introduction of conductive materials (such as metal powder, graphite, soot) to polymer dielectric [1]. 

These materials [164-166], consisting of precious metal (e.g., ruthenium) oxides coated on baser metals (e.g., titanium), have already had a major impact on the chloralkali industry as replacements for graphite. Sometimes an inactive oxide (e.g. Ti02) is mixed with the catalyst to improve corrosion resistance [167]. These types of electrodes may in many cases be used where previously only platinum could be employed and may thus make a number of organic electrosyntheses possible that were not considered industrially viable due to the price of platinum. 

The various sections in the book cover selected categories of corrosion resistant materials, such as synthetic resins and polymers rubbers and elastomers cements, mortars, and asphalt ferrous alloys nonferrous metals and alloys and glass, ceramics, and carbon-graphite. A separate section presents a group of 13 tables which compare the anticorrosive merits of a cross section of commercial engineering and construction materials essential to industry. The tables in the book represent selections taken directly from manufacturers literature made at no cost to, nor influence from, the makers or distributors of these materials. 

Metal dusting is related to carburization and has been reported in similar industries. In this form of degradation, the corrosion products appear as fine powders (hence the term dusting) consisting of carbides, oxide, and graphite (soot). The morphology of attack can be localized... 

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