Spelter Spelter Spelter, while sometimes used merely as a synonym for zinc, is often used to identify a zinc alloy. In this sense it might be an alloy of equal parts copper and zinc, i.e. a brass, used for hard soldering and brazing, or as an alloy, containing lead, that is used instead of bronze. In this usage it was common for many 19th-century cheap, cast articles such as candlesticks and clock cases and early 20th-century Art Nouveau ornaments and Art Deco figures. Early twentieth-century Art Nouveau and Art Deco figures and lamps were often made of spelter. The metal has
Group 6 element 1924. For about a century after its isolation, molybdenum had no industrial use, owing to its relative scarcity, difficulty extracting the pure metal, and the immaturity of the metallurgical subfield. Early molybdenum steel alloys showed great promise in their increased hardness, but efforts were hampered by inconsistent results and a tendency toward brittleness and recrystallization. In 1906, William D. Coolidge filed a patent for rendering molybdenum ductile, leading to its use as a heating element for high-temperature furnaces and as a support for tungsten-filament light bulbs; oxide formation and degradation require that moly be physically sealed or held in an