Chromium is a chemical element with the symbol Cr and atomic number 24. It is the first element in group 6 of the periodic table. Chromium is a steely-gray, lustrous, hard and brittle metal which takes a high polish and has a high melting point. Chromium is mainly used as an alloying element in stainless and tool steels.
Chromium is one of the most important metal components of alloys because, when added to steels and cast irons, it improves their mechanical properties and increases their corrosion resistance. It also improves the forming and machining characteristics of steels. Chromium is used in many different alloys. In stainless steels, chromium increases strength and corrosion and oxidation resistance. In tool steels, chromium increases hardness, wear resistance, and red-hardness (the ability of steel to be hardened at high temperatures).
Chromium is also used in the production of alloys such as superalloys and nickel-base alloys. Superalloys are used extensively for components in gas turbine engines because of their high temperature and oxidation resistance. Chromium is used in nickel-base alloys for turbine blades, pumps, and hydraulic components.
Chromium is also used in pigments and coatings. Chromium oxide (Cr2O3) is used as a pigment in paints and plastics, and as an abrasive in polishing compounds. Chromium compounds are also used in tanning leather and in metal plating and dyeing. Chromium can also be used in metal finishing to protect the surface from corrosion and to give the metal greater wear resistance, shine, and durability.
Chromium is an essential trace element for human nutrition, although in trace amounts only. As such, it plays a role in the health of the cells, organs, and systems in our bodies. Chromium helps insulin interact with cells to allow glucose to enter and provide energy. It also helps control fat and cholesterol levels in the blood and helps the body utilize proteins and fats. A deficiency in chromium is associated with diabetes, high blood pressure and heart disease.
Chromium is a toxic substance and can be hazardous if inhaled or ingested at concentration levels over the limit set for human health. Besides this, it can cause skin irritation and other allergic reactions, and overexposure can result in respiratory illnesses, neurological damage, and harm to our reproductive system. Chromium can also contaminate food and water supplies, leading to a risk of cancer, developmental and reproductive problems.
