Introduction to Corrosion Chemistry

Abstract

Corrosion - introduction. Corrosion is a general term used to describe various interactions between a material and its environment leading to a degradation in the material properties. Interaction with ambient oxygen can cause the formation of oxide layers via diffusion controlled growth. It involves the deterioration and consequently loss of solid metallic structure due to the chemical (dry gases, moisture, liquid, ionic solutions, microbes, etc.) or electrochemical (micro-cell formation like Daniel cell) reactions resulting from the potential difference in the structure and presence of a suitable electrolyte (salt-water). The process of corrosion is a surface phenomenon whose rate depends upon various factors such as temperature, the presence of harmful chemicals in the environment, ionic species, as well as humidity. Once the surface is breached the process of deterioration continues within, thereby making the structure vulnerable to stress and load. The combination with acid in the environment generated via., possible chemical reactions speed up the process resulting in the reduction of the life span of metal structure. Corrosion can be sub-divided into many forms such as pitting, galvanic, intergranular, stress, and others. All these can affect the structural integrity by weakening the metallic units within any construction by corroding rods/wires, water pipelines (leakages), metallic bases, electrical units, etc. Few of these examples are shown in. Corrosion of steel is a spontaneous electrochemical process that takes place in the presence of a solution containing dissolved oxygen. This process includes the delocalization of metal ions through oxidation into the solution at the anode (active area) and mobilization of electrons through reduction of metal to an acceptor such as oxidizing agents, or oxygen or hydrogen ions at cathode (less active area). The mechanism of corrosion involves the release of electrons from the metallic surface into the electrolyte in the presence of oxygen. This process occurs due to the tendency of metals to return to their natural oxidation state.

Keywords: Corrosion, Chemistry, oxidation