EFFECT OF TEMPERATURE ON CORROSION INHIBITION OF COPPER - NICKEL ALLOY BY TETRAETHYLENEPENTAMINE UNDER FLOW CONDITIONS

Abstract

ABSTRACT The corrosion of copper – nickel alloy in hydrochloric acid was investigated at different temperatures, inhibitor concentrations, and corrosive solution rotation rates. Weight loss technique was used to evaluate the corrosion rate data. Tetraethylenepentamine was used as organic corrosion inhibitor, while hydrochloric acid was the corrosive solution. Different parameters, such as inhibitor efficiency, activation energy were obtained. Corrosion rate increased with both temperature and acid rotation rate, while it decreased with increases of Tetraethylenepentamine concentration. Maximum inhibitor efficiency was at lower level of temperature, acid rotation rate and higher level of inhibitor concentration. Keywords: Corrosion inhibition; hydrochloric acid; kinetic parameters; fluid flow. e-mail: aneesdr@gmail.com INTRODUCTION Copper alloys are widely used metal with an extensive industrial application. The study of its corrosion inhibition is a subject of great importance which has attracted much attention. In fact, the corrosion of metallic materials in acidic solution causes considerable costs [1]. One of the most practical methods for protection against corrosion in acidic media is use of inhibitors [2-16]. Most of the efficient organic inhibitors are the compounds which contain hetero-atoms such as oxygen, nitrogen, sulfur, and phosphorus which allowed adsorption on the metal surface [17]Various corrosion inhibitors were suggested for copper inhibition in acidic solutions, but not all of them can be used for a long time [18, 19]. However, it remains an important objective that one can either find a new inhibitor or to improve the efficiency of a known inhibitor by applying a synergistic technique [20]. Many organics compounds are widely used as inhibitors in various industries. The organic molecules adsorb on the metal surface through heteroatom, such as nitrogen, oxygen, and sulfur, blocking the active sites and generating a physical barrier to reduce the transport of corrosive species to the metal surface [21, 22]. The amines are an interesting group of nitrogen containing organic compounds, which act as inhibitors in the dissolution of metals in aggressive media by adsorbing at the metal-solution interface. They have been studied as corrosion inhibitors for various metals in several media [23, 24]. The inhibiting action of these inhibitor compounds is usually attributed to their interactions with the copper surface via their adsorption. Polar functional groups are regarded as the reaction center that stabilizes the adsorption process. However, the adsorption of an inhibitor on a metal surface depends on the nature and the surface charge of the metal, the adsorption mode, its chemical structure, and the type of the electrolyte solution [25 – 27]. The aim of present paper was to study the effect of temperature and rotation rate on the corrosion of copper – nickel alloy in hydrochloric acid in presence of Tetraethylenepentamine as a corrosion inhibitor.