Tin of protons. It has two main allotropes: at room temperature, the stable allotrope is β-tin, a silvery-white, malleable metal, but at low temperatures it transforms into the less dense grey α-tin, which has the diamond cubic structure. Metallic tin does not easily oxidize in air. The first tin alloy used on a large scale was bronze, made of tin and copper, from as early as 3000 BC. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony, and lead, was used for flatware from the Bronze
Melchior (alloy) Melchior (alloy) In metallurgy, melchior is an alloy of copper, mainly with nickel (5–30%). Its name originates from , which in turn is distorted , honoring the French inventors of the alloy, Maillot and Chorier. The term melchior sometimes refers not only to the copper-nickel alloys, but also ternary alloys of copper with nickel and zinc ("nickel silver") and even a silvered brass. Melchior is easily deformable by application of pressure, both in the hot and cold state. After annealing, it has a tensile strength of about 40 kg/mm. The most valuable property of melchior is its high resistance to