We must recognize that there are very few laboratories in the world that use highly concentrated radioactive water. It is not a question of radioactive water traces present in light water, but the reverse. By its nature, this medium is very reactive and its properties are completely different that in light water. Corrosion of stainless steels or super alloys are thus completely different and no comparison is possible.

Iron

Iron (Latin ferrum, symbol Fe) is magnetic, malleable, silvery white metallic element. Its' atomic number is 26 and it is one of the transition elements of the periodic table.

(WHY TREAT YOUR COOLING WATER?- Part 1)

Dissolved gases, improper pH control or formation of differential aeration cells under deposits cause corrosion to be undoubtedly the single most significant factor leading to the premature deterioration of HVAC equipment and piping. In its most insidious form, pitting, is only revealed when the equipment fails. Failures of this type can be catastrophic, leading to costly downtime for repairs and equipment replacement, personal discomfort and even total plant shutdown. In a cooling tower, the water trickles down a large surface area in order to air-cool the water. The natural evaporation provides the cooling necessary to reuse the water. As water evaporates, minerals and contaminants in the water concentrate. These minerals and contaminants will eventually reach a concentration where they will cause problems and interfere with the performance of both the tower and the cooling system, itself. Fouling and corrosion of the cooling tower can impact treatment, and impact heat transfer losses causing decrease in efficiency and increased power consumption. Biofouling can also destroy cooling towers if they are made of lumber. Corrosion can occur on metal parts.

The presence of large amounts of yeast or fungi can indicate a low pH, or existence of fermentative conditions. There are more than 75,000 species of yeast and fungi, which include mold, smut, rust and mildew. They may be colorless or cover the entire color spectrum. Most grow best in warm, dark, moist places. Most are aerobic with low oxygen demand. A few, including yeast, are anaerobic. Fungi can grow on almost any surface and are considered an attributing factor to wood deterioration. Both yeast and fungi are commonly transported by air currents. They are relatively large and can easily be identified with microscopic analyses. Algae primarily occur in the tower deck area because most species require sunlight for photosynthesis and growth.

Electrochemical corrosion involves two half-cell reactions

• an oxidation reaction at the anode, and
• a reduction reaction at the cathode.

Biofouling can destroy cooling towers if they are made of lumber. Corrosion can occur on metal parts. More seriously, such contaminants can be harmful to humans coming in contact like operational and maintenance personnel. The most notable example has been the outbreaks of Legionnaires' disease, affecting people in hotels, hospitals, office buildings, and other locations, who have come into contact with cooled air from an air conditioning system contaminated from cooling tower water of the air conditioning plant. Algae are the typical Biological species found that could cause corrosion and Biofouling. Algae can be branched or straight. It can be curled or in small free floating clusters with a slime coating.

If you have an older car, the corrosion occur at the joints between body parts and under paint films; and once corrosion starts, it tends to feed on itself.

The potential difference between an anode and a cathode can be measured by a voltage measuring device. The absolute potential of the anode and cathode cannot be measured directly. Defining a standard electrode, all other potential measurements can be made against this standard electrode. If the standard electrode potential is set to zero, the potential difference measured can be considered as the absolute potential.

A corrosion inhibitor is a chemical compound that reacts with a metallic surface, or the environment this surface is exposed to, giving the surface a certain level of protection (see corrosion costs study findings).

Some Types of Corrosive Attack on Metals:

• General corrosion, Galvanic cells, Under-deposit corrosion, CO2 corrosion,
• Top-of-line corrosion, Weld attack, Ringworm corrosion, H2S corrosion,
• Hydrogen Induced Cracking(HIC), Erosion corrosion, Corrosion Fatigue
• Crevice Attack, De-alloying, Microbiological corrosion, Intercrystalline corrosion,
• Pitting corrosion, Stress Corrosion Cracking, Hydrogen Embrittlement.

There are many kinds of corrosion, which can attack metals, can cause leaks, explosions, fire, in equipment like pipelines and pressure vessels. But they also can cause cracks and embrittlement of metals used for construction. Corrosion is often identified with atmospheric rusting of iron base alloys, but that is only a subclass of one of the many possible mechanisms of corrosive attack.

Erosion is a broadly defined group of processes involving the movement of soil and rock. This movement is often the result of flowing agents, whether wind, water, or ice, which sometimes behaves like a fluid in the large mass of a glacier.

Fluorine (F2) is the element of group VIIA i.e. the Halogen Group elements of the periodic table, which is a poisonous pale yellow gaseous element and most reactive. It reacts violently with water liberating oxygen and forming hydrofluoric acid (HF). It even reacts with some of the normally inert noble gases such as Krypton (Kr) and Xenon (Xe). Most inorganic acids are very corrosive to materials. Hydrofluoric acid attacks glass, concrete, and many metals. It also attacks carbonaceous natural material such as woody materials, leather, and rubber.