Molybdenum Properties:
Molybdenum with 42 atomic number and 95.96 atomic weight, has highest melting temperatures in comparison to all the elements. It's density is 10.22 g/cm3, only 25% greater than of iron. 4.8 x 10-6 / K at 25C is its coefficient of thermal expansion, which is lowest in comparison to other engineering materials. On the other hand, its thermal conductivity which is 138 W/m K at 20C is more exceeds many elements.
Production;
Powder metallurgy techniques are followed for the production of Molybdenum metal.
Molybdenum metal is produced by hydrogen reduction of pure molybdic oxide or ammonium molybdate.
Mo powder in this process is hydrostratically compacted and sintered at the temperature of around 2100C. Under the temperature, ranging from 870C to 1260C, hot working is carried out. Moly when heated at the temperature more than 600C in air forms a volatile oxide, which is why high temperature applications are carried out in only non-oxidizing or vacuum environments. At high temperature up to 1900Celsius, this alloy has the mechanical stability and strength. This alloy can better tolerate imperfections and brittle fracture in comparison to ceramics, because of the features, like toughness and high ductility.
Historically, both stages were accomplished by pushing boats loaded with powder through tube furnaces containing a flowing hydrogen atmosphere. Rotary furnaces, where powder is fed continuously through a rotating inclined tube in a flowing hydrogen atmosphere, are becoming common in first stage reduction operations, where they provide increased production efficiencies.
Uses:
Molybdenum metal is often added to steel and cast irons with the purpose to improve their characteristics, like temperature strength, hardness, weldability and resistance to corrosion. When added to nickel-base alloys, molybdenum metal improves corrosion resistance and high-temperature creep deformation resistance. All specialized applications demand Molybdenum metal and Molybdenum metal alloys, given to the properties, for instance: