C. Foret, G. Stoianovici, G. Chaussec, A. de Bache, C. zum Kolk, W. Hater

Metal corrosion in industrial water systems like cooling circuits is a major problem. Excessive corrosion does not only lead to serious damages of installations but also causes significant environmental and economic repercussions. To reduce or eliminate these problems, water used in cooling circuits is usually chemically processed and treated with inhibitive formulations containing corrosion inhibitors.

In the past, efficient protective treatments of carbon steels were based on inorganic inhibitors (e.g. chromates, nitrites) [1] but today their use is restricted due to their high toxicity. Since the 1960’s, other treatments using organic compounds like phosphonates, molybdates and amines have been proposed because of their non-toxic nature. Nevertheless, high concentrations are necessary to obtain good inhibition [2, 3].

For many years, the prevention of corrosion in cooling systems is achieved by film forming amines (FFA) which are often referred to as fatty amines or polyamines [4, 5, 6]. They are able to form a mono-molecular film or layer adsorbed on the metal surfaces, which constitutes a homogeneous protective barrier against corrosion.

Today, due to a lack of knowledge and systematic research about the influence of chemical structure on the anticorrosion properties, especially for FFA, this paper presents the results of studies with new inhibitive formulations based on amines for cooling systems.

Comparative studies have been carried out to evaluate the efficiency of film forming amines (FFA), and to optimize their inhibitive properties against the corrosion of carbon steel.

In this aim, the present work is devoted to study the behavior of the carbon steel, in presence of different inhibitive formulations based of FFA of different structures, by steady-state electrochemical measurements, impedance spectroscopy measurements using a rotating disc electrode and pilot test in laboratory. From the data obtained, it is intended to develop structure/property relations in order to find optimal corrosion inhibitors also taking into account ecological and economical aspects.

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