Corrosion costs

Many reaction schemes have been proposed (161,162). All reaction schemes ate designed such that reaction steps having positive A. " values are operated at high (625—725°C) temperatures, whereas reaction steps having negative AA values are operated at low (about 225°C) temperatures. The purpose is to lower the free energy change, ie, the work requirement, and increase the thermal requirement, for improved efficiency. Other considerations, such as reaction kinetics, corrosion, cost of materials, and side reactions must also be taken into account. 

Estimates were made by Uhlig in the USA. Worner in Australia, and Vernon in the UK, in which the cost of protection and prevention were added to the cost of deterioration due to corrosion. These early estimates were made by individual scientists from cost information from new major industries scaled up to a national level, and were of the order of 1-1.5% of GNP. More detailed estimates were subsequently made by the Committee on Corrosion and Protection (the Hoar Committee) in the UK, and Payer etal. for the National Bureau of Standards in the USA. The later estimates were around 3.5-4% of GNP, the higher figure reflected factors not covered in the earlier surveys, which were, moreover, based on organisations which had probably already taken action to minimise their corrosion costs. Estimates have since been made for other European countries which tend to confirm the higher figure. 

Corrosion is the deterioration of a material by reaction with its enviromnent. Although the term is used primarily in conjunction with the deterioration of metals, the broader definition allows it to be used in conjunction with all types of materials. We will limit the description to corrosion of metals and alloys for the moment and will save the degradation of other types of materials, such as polymers, for a later section. In this section, we will see how corrosion is perhaps the clearest example of the battle between thermodynamics and kinetics for determining the likelihood of a given reaction occurring within a specified time period. We will also see how important this process is from an industrial standpoint. For example, a 1995 study showed that metallic corrosion costs the U.S. economy about 300 billion each year and that 30% of this cost could be prevented by using modem corrosion control techniques [9], It is important to understand the mechanisms of corrosion before we can attempt to control it. 

The damage caused by corrosion costs several percent of the gross national product of technologically advanced countries Nowhere else in the whole of science could so much money be saved by the application of the work of so few. 

Table 1.1 Corrosion costs in the United States (billions of dollars)...

The corrosion costs in Canada8 as of 2003, along with the various sectors are given in Tables 1.2 and 1.3. 

It is evident from the data presented on the economics of corrosion that corrosion costs amount to about 2-4% of GNP, and about 25% of the costs are avoidable by adopting corrosion control measures. The measures taken to combat corrosion in UK, USA, Australia, China and Canada have been discussed.18 The following is a short summary of the activities in various parts of the world to combat corrosion. 

Country Year Corrosion costs ( ) Percent of GNP Avoidable cost Reference... 

Corrosion Costs and Preventative Strategies in the United States, A Review by Materials Performance, MP Supplement, July 2002. 

Design Costs. These include the costs of special materials (stainless steel, copper alloys, etc.) when used because of corrosion, costs of extra materials (heavier sections on beams, etc.) and special processing. These are incurred during manufacture. 

There are striking similarities as well as differences in the results. First is the total cost. Within the range of uncertainty, total fracture costs and corrosion costs are both of the GNP, which, considering the greater completeness of these studies, correlates well with previous studies. However, the similarity of the corrosion and fracture results must be somewhat fortuitous since the corrosion study was limited to metals, while the fracture study included all materials. Similarly, the avoidable costs of approximately 20 of the total for corrosion (for technical reasons, this number has a large uncertainty (]J) and 29 of the total for fracture also correlate well, and correlate with previous studies (Table I). 

Second, an attempt may be made to arrive at the actual costs of acid rain. Since acid-rain is a form of atmospheric corrosion, the total costs of corrosion for metals of approximately of the GNP would certainly be a high upper limit for the costs of acid rain on metals. Even the inclusion of irreplaceable artistic and architectural items in the cost of acid rain would appear to leave the total costs well short of the total corrosion costs. 

The overall national costs of corrosion of metal and fracture of all materials are each about of the GNP, 20-30% of which could be saved with complete use of economic best practice. The costs of wear, which are not as well known, raise the total costs of these three degradative processes to somewhat over 10% of the GNP. The costs are expected to be comparable in other industrialized nations. From the results in Ref. 18, the extra corrosion costs of metals associated with air pollution are about 0.15% of the GNP, or H% of the total corrosion costs. 

F. W. Fink, F. A. Butner, and W. K. Boyd, "Technical-Economic Evaluation of Air-Pollution Corrosion Costs on Metals in the U.S., Report to Air Pollution Control Office, Environmental Protection Agency, Feb. 19, 1971, NTIS, PB198-453. 

TABLE 3-4 Estimated 1982 Corrosion Costs for the United States... 

Ballard, D., "Cut Energy, Chemical and Corrosion Costs in Amine Units, Energy Prog. 6(2), 1986, p. 112. 

Corrosion Costs and Preventive Strategies in the United States, Tech Brief FHWA-RD-01-157, US Dept, of Transportation. 

Challenges in Corrosion Costs, Causes, Consequences, and Control, First Edition. V. S. Sastri. 2015 John Wiley Sons, Inc. Published 2015 by John Wiley Sons, Inc. 

Development of comprehensive lists of corrosion cost elements to be used in the analysis of total costs and costs in individual sectors. 

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