What Is Rust

Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. Although some people refer to rust generally as "oxidation," that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. 

If sodium is present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.

Some pieces of iron or steel are thick enough to maintain their integrity even if iron oxide forms on the surface. The thinner the metal, the better the chance that rusting will occur. Placing a steel wool pad in water and exposing it to air will cause rusting to begin almost immediately because the steel filaments are so thin. Eventually, the individual iron bonds will be destroyed, and the entire pad will disintegrate. 

Rust formation cannot be stopped easily, but metals can be treated to resist the most damaging effects. Some are protected by water-resistant paints, preventative coatings or other chemical barriers, such as oil. It also is possible for one to reduce the chances of rust forming by using a dehumidifier or desiccant to help remove moisture from the air, but this usually is effective only in relatively small areas. 

Steel is often galvanized to prevent iron oxide from forming; this process usually involves a very thin layer of zinc being applied to the surface. Another process, called plating, can be used to add a layer of zinc, tin or chrome to the metal. Cathodic protection involves using an electrical charge to suppress or prevent the chemical reaction that causes rust from occurring.

What is a Metric Ton

A metric ton is a unit of measurement based on the metric system, rather than the standard system used in the United States. A metric ton is equivalent to 1,000 kilograms, and is strictly speaking a megagram, being one million grams.

The word most likely comes from the Latin word tunna, which is a word for a cask. Since a large cask full of something would weigh roughly a metric ton, this origin is commonly accepted. The word has been in use for quite some time, although previously the spelling was more often tunne.

The metric ton is often spelled as tonne, and in the United States may also be called a tonneau. A metric ton is not to be confused with the short ton unit, known simply as a ton in the system used in the United States. This ton is equal to 2000 pounds, or roughly 907kg. It should also not be confused with a long ton, a unit no longer in common usage in the United States, which is equal to 2240 pounds.

The official symbol for the metric ton in the International System of Units (SI) is simply ‘t’. Although all of the standard prefixes can be used with the metric ton, in practice the most common ones are the same ones used with the short ton. The kilotonne and megatonne are the only two units commonly seen outside of the metric ton itself. 

Kilotonne and megatonne may be used as metric for measuring energy release. This makes use of the metric ton by connecting it with the explosive TNT, as a way of calculating the force of an explosion. A metric ton of TNT releases roughly 4.19 X 10^9 Joules of energy, with a kilotonne releasing 4.19 X 10^12, and a megatonne releasing 4.19 X 10^15. To put this in some context, the Hiroshima bomb was equal to about twenty kilotonnes of TNT, while a modern nuclear missile could fall closer to the twenty megatonne range.

Because of the similarity in pronunciation — and in some circles, spelling — there can often be confusion between a short ton, a long ton, and a metric ton. In general, in the metric-using world the term ton or tonne alone will be used to refer to a metric ton, while the distinction long ton or short ton will be used to refer to the measure of the standard or Imperial system. In the United States, the term ton will be used to refer to a short ton, although in some industries — such as freight — a ton may be assumed to be a long ton. The term metric ton is then used to distinguish the metric unit. As a rule of thumb, it is a good idea to distinguish which unit of measurement you intend, if there is any doubt that your listeners might misconstrue your meaning.

What Is Rust

Rust is another name for iron oxide, which occurs when iron or an alloy that contains iron, like steel, is exposed to oxygen and moisture for a long period of time. Over time, the oxygen combines with the metal at an atomic level, forming a new compound called an oxide and weakening the bonds of the metal itself. 

Although some people refer to rust generally as "oxidation," that term is much more general; although rust forms when iron undergoes oxidation, not all oxidation forms rust. Only iron or alloys that contain iron can rust, but other metals can corrode in similar ways.

The main catalyst for the rusting process is water. Iron or steel structures might appear to be solid, but water molecules can penetrate the microscopic pits and cracks in any exposed metal. The hydrogen atoms present in water molecules can combine with other elements to form acids, which will eventually cause more metal to be exposed. 

If sodium is present, as is the case with saltwater, the corrosion is likely to occur more quickly. Meanwhile, the oxygen atoms combine with metallic atoms to form the destructive oxide compound. As the atoms combine, they weaken the metal, making the structure brittle and crumbly.

Some pieces of iron or steel are thick enough to maintain their integrity even if iron oxide forms on the surface. The thinner the metal, the better the chance that rusting will occur. Placing a steel wool pad in water and exposing it to air will cause rusting to begin almost immediately because the steel filaments are so thin. Eventually, the individual iron bonds will be destroyed, and the entire pad will disintegrate. 

Rust formation cannot be stopped easily, but metals can be treated to resist the most damaging effects. Some are protected by water-resistant paints, preventative coatings or other chemical barriers, such as oil. It also is possible for one to reduce the chances of rust forming by using a dehumidifier or desiccant to help remove moisture from the air, but this usually is effective only in relatively small areas. 

Steel is often galvanized to prevent iron oxide from forming; this process usually involves a very thin layer of zinc being applied to the surface. Another process, called plating, can be used to add a layer of zinc, tin or chrome to the metal. Cathodic protection involves using an electrical charge to suppress or prevent the chemical reaction that causes rust from occurring.