"Brearley launched his 'rustless steel' (later renamed... 'stainless') on the world with great gusto"
IP Review: Accidental Inventions
Stainless steel is an alloy of iron and chromium. It does not corrode in contact with air and water, stays bright, and can be polished. The chromium, which has a great affinity for oxygen, protects the iron by forming a molecular layer of chromium oxide at the surface, preventing contact between iron and oxygen.
Harry Brearley (1871-1948) was head of the research team at the Brown Firth company in Sheffield, England, when the firm was commissioned to develop an erosion-resistant metal for gun barrels. Brearley experimented with iron-chromium alloys, which were known to have higher melting points than steel. He varied the proportion of chromium between 6 and 15 percent and also changed the carbon content until he developed an alloy with 12.8 percent chromium and 0.24 percent carbon. The alloy was impressively resistant to corrosion and Brearley recognized the potential for its use in cutlery.
Brearley was not the first to observe the properties of chromium-iron alloys. French metallurgist Pierre Berthier (1782-1861) had made such alloys, and other metallurgists were working on the same problem at the same time, notably Leon Guillet who developed an iron-nickel-chromium alloy in 1906. In 1908 the Krupp Iron Works in Germany manufactured chrome- nickel steel for the hull of a yacht, which sadly sank.
