Adding new coatings can help change the properties of steel The biggest challenge for researchers in developing the surface coating was figuring out a way to protect the steel without affecting its performance The researchers used an electrochemical technique to place an extremely thin film of small and rough patches of tungsten oxide known as islands directly onto a steel surface Tungsten oxide is a chemical compound that contains oxygen and the element tungsten which is very hard If one part of the tungsten film is destroyed or damaged the remaining tungsten oxide islands still protect the steel because the islands are not connected 6
The Harvard researchers tested the surface coating by scratching it with a variety of tools including stainless steel tweezers and instruments with diamond tips They hit it with thousands of hard heavy beads They also tested the surface coating’s ability to repel a variety of liquids including water oil fluids containing bacteria and blood and highly corrosive liquids The coating repelled all of the liquids and resisted bacterial contamination In addition the researchers discovered during their testing that steel coated with tungsten oxide was stronger than steel without the coating The Harvard surface coating could be used to improve many steel products Using it to coat steel medical tools such as implants and scalpels is one of the most promising future applications The surface coating may one day be used to improve 3-D printing Layer by layer 3-D printers build three-dimensional objects Like all steel objects the steel components of 3-D printers can become corroded When printing with thick and sticky materials the steel nozzles often clog Covering the nozzles with the new coating could help them deliver the material smoothly and evenly With less clogging the lifespan of the printer’s steel nozzles would improve The US Navy may also benefit from the steel coating Every year the navy spends millions of dollars cleaning the hulls of its ships Barnacles and algae cling to steel hulls These organisms create drag in the water which decreases the ship’s performance and increases the amount of fuel it uses Current antifouling paints contain ingredients that are harmful to the environment An improved steel coating could be a cleaner cheaper alternative 7
Cutting-edge 3-D printers are among the many products that could see benefits from new steel technologies STEEL THE BACKBONE OF MANUFACTURING Steel is an alloy in which iron is mixed with carbon Steel can contain other metals such as manganese nickel or chromium Different types of steel have different properties Changing the amount of carbon in steel can change these properties For example the steel in a pair of scissors 8
is harder than the steel in a can of fruit This occurs because the steel in the scissors contains much more carbon than the can increasing its hardness Innovations such as the tungsten oxide coating are making steel more useful than ever The steel industry continues to be a cornerstone of American business A unique and vital material steel is an integral part of a huge variety of products and structures It is no exaggeration to say the steel industry has helped to build the modern United States Steel provides the structure and support for famous landmarks such as the Golden Gate Bridge in San Francisco California the Gateway Arch in Saint Louis Missouri and the One World Trade Center skyscraper in New York City Carbon Steel The majority of steel produced is carbon steel which contains a small amount of carbon Steels with between 0 05 and 0 25 percent carbon are low-carbon steels They are relatively soft and easy to shape Steels with up to 1 percent carbon are called high-carbon steels 2 High-carbon steels are usually hard and brittle A variety of products are made from carbon steels such as car bodies steel cans and engine parts In addition to building these landmarks steel touches almost every part of modern life People around the world rely on steel for housing transportation energy production tools health care and food and water supplies We enjoy the benefits of steel in all aspects of our lives From the moment we wake up until we go to sleep at night we rely on steel in almost every aspect of our day says Thomas Gibson president and CEO of the American Iron and Steel Institute He continues 9
