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Acidization is one of the most important techniques to increase the productivity of crude petroleum oil and gas wells. The effective way for protecting these oil well tubular materials is by using corrosion inhibitors during the acidization process. The present study deals with the evaluation of inhibition effect of ethanolamines on oil well tubular materials of grade N‐80 steel in 15 per cent hydrochloric acid at room temperature with 0‐2 per cent amine concentrations. The amines such as mono, di and triethanolamine were studied for their inhibiting capacity by mass loss method, DC polarization method and AC Impedance method. The inhibitor efficiency increases with increasing concentration of amines. Monoethanolamine is found to be more effective than the other two amines.

It is now fairly well established that steel reinforcements need some additional protection and various types of coatings such as fusion‐bonded epoxy, galvanizing and cement slurry have been used. Evaluation of such coated rebars in aggressive marine conditions is done usually by conducting some accelerated corrosion tests. These accelerated corrosion tests cannot be truly representative of field conditions and they often give higher corrosion rates. Validity of such tests becomes questionable. In the present work, corrosion rates of cement slurry‐coated rebars, obtained by ASTM impressed voltage test, salt‐spray test, precracked cantilever model slab test, alternate wetting and drying test and macrocell corrosion test, have been compared with uncoated rebars. It is shown that for a passivating type of coating such as cement slurry, accelerated corrosion tests could be equally valid.

To reduce the corrosion of oil‐ and gas‐well equipment during acid treatment, the acid must be inhibited. The behaviour of N‐80 oilfield material in 15 per cent hydrochloric acid solution inhibited by different inhibitor formulations containing amine, ester and a quaternary ammonium compound was studied at 303K for five hours by the mass loss method. The corrosion rates were obtained by polarisation. Impedance studies were carried out to evaluate the performance of the inhibitor formulations. It was found that the formulation containing 3,000ppm amine, 1,000ppm ester and 1,000ppm quaternary ammonium compound was effective for the specific oil‐well tubular material.

To analyze the different approaches used to estimate the cost of corrosion and understand the limitations so as to have proper appropriation in future appraisals.

Four well‐known approaches to analysis of cost of corrosion viz., the Uhlig method, the Hoar method, NBS‐BCL input/output method and net present value method have been considered in great detail and the impact of these approaches on corrosion economy in different countries has been highlighted.

Uhlig method of estimating corrosion cost always gives a conservative estimate of the direct cost of corrosion. The direct cost of corrosion, as estimated by the Hoar method, is found to be somewhat higher than is the estimate made using the Uhlig method, as shown by Shibata of Japan. The NBS‐BCL method of input/output analysis, though apparently more scientific, is subject ultimately to uncertainties in quantifying the capital cost and intermediate output. The net present value method appears to be more realistic than do other approaches as it enables a life cycle costing of each structure/facility to be made and arrives at the most cost‐effective corrosion control method. Even though all the above four approaches enable an estimation of direct cost of corrosion, there is no standard approach to assess the indirect cost of corrosion.

In a developing economy, each and every industry has to go for systematic corrosion auditing in order to identify and adopt the most appropriate corrosion control measures and effect considerable savings. This paper would be of immense use in that regard.

The most economical way of protecting pipelines is through the application of organic coatings and wrappings. To make the protection foolproof at holidays and pores, cathodic protection is also applied. At coating holidays, the pipelines act as the cathode generating hydroxyl ion and hydrogen electrochemically. Extensive studies have been carried out using samples of mild steel pipe coated with reinforced coal tar enamel coating to investigate the role of hydrogen and hydroxyl ion on cathodic disbondment. The testing material is subjected to different environmental conditions like pH, aeration and addition of different anionic species. A mechanism has been proposed to describe the individual role of hydroxyl ion and hydrogen in the process of disbondment.

Epoxy‐resin‐based paints generally offer very good corrosion‐protective properties and are widely used in harsh environments such as the sea. They are two‐pack systems, the curing agent normally used being polyamines or polyamides. Such systems find extensive use on structures exposed to dry conditions. When substrates lie under water or are constantly exposed to the wet, the above system is impracticable due to poor adhesion. For these environments, the curing agent has to be modified, and in such circumstances ketimines have been found to work. Many amines and ketones are used to obtain ketimines. The ketimine in contact with water hydrolyses, releasing a free amine, which in turn reacts with the epoxy resin and so curing takes place in situ. Reports on a study of effective ketimines in various coating systems.

Aluminium alloys are being employed very widely as galvanic anodes for cathodic protection. Aluminium‐zinc‐mercury and aluminium‐zinc‐indium are the popular alloys that are used as anodes. In general, the alloying ingredients activate aluminium and maintain uniform dissolution. In the present investigation, the role of addition of gallium in the ternary alloy of aluminium‐zinc‐indium has been studied by making use of polarisation studies, capacity measurements and galvanic current measurements.

The corrosion behaviour of Inconel 600 and 601 alloys has been evaluated by DC polarisation method in orthophosphoric acid solution of concentrations 0.5N to 15N. The passivation range from + 200mV to + 800mV has been observed for 601 alloy. In the case of Inconel 600 a less passivation range in comparison with Inconel 601 is observed. In addition, the passivation current has been found to be higher than that of 601 alloy. Tafel polarisation study indicates that Inconel 601 alloy is more corrosion resistant than Inconel 600.

Concrete forms a major component of the national infrastructure. Corrosion of reinforced steels embedded in concrete has recently received wide attention in R&D programmes. Different cases have been reported showing failures of concrete structures which means huge loss. An attempt has been made to identify the different factors affecting the corrosion of embedded steel. Comparative evaluation of different protective schemes use of additives in concrete admixtures and the application of the cathodic protection technique has been discussed.

Reports on corrosion and microfouling analyses carried out in natural pondwater using mild steel under static condition. Corrosion rates were measured at regular intervals by weight loss and polarization techniques. The corrosion rate obtained by weight loss measurement was found to be less in the biotic system, but corrosion current obtained by polarization studies was higher in the biotic than abiotic system. Surface analysis by x‐ray diffraction indicates that bacteria with organic nutrients inhabited the corrosion to formation of surface film.