Origin of molybdenum metal

Although molybdenum was discovered in the late 18th century, it was already in use before its discovery, e.g. in the 14th century, when molybdenum-containing steel was used to make sabres in Japan, and in the 16th century, when molybdenite, because of its similarity in appearance and properties to lead, galena and graphite, was used as graphite, and was collectively referred to by the Europeans of the time as " molybdenite".

In 1754, the Swedish chemist BengtAnderssonQvist tested molybdenite and found that it did not contain lead, so he thought that molybdenite and galena were not the same substance.

In 1778, the Swedish chemist Scherer found that nitric acid did not react with graphite, but reacted with molybdenite to obtain a white powder, which was boiled with an alkaline solution and crystallised into a salt. He thought that this white powder was a metal oxide, mixed with charcoal after strong heat, and did not get the metal, but when it was heated with sulfur together but got the original molybdenite, so he thought that molybdenite should be a kind of unknown element of the mineral.

According to Scherer's inspiration, in 1781, the Swede Jelm used the "carbon reduction method" to isolate a new metal from this white powder, and named the metal "Molybdenum".

Alloys

Molybdenum is most consumed in the iron and steel sector, where it is mainly used in the production of alloy steels (approx. 43% of total molybdenum consumption in iron and steel), stainless steels (approx. 23%), tool and high-speed steels (approx. 8%), and cast irons and rolls (approx. 6%). Most of the molybdenum is used directly in steelmaking or cast iron after being briquetted as industrial molybdenum oxide, while a small proportion is first smelted into ferromolybdenum and then used in steelmaking. Molybdenum as an alloying element in steel has the following advantages: it increases the strength and toughness of the steel; it improves the corrosion resistance of the steel in acid and alkaline solutions and liquid metals; it increases the wear resistance of the steel; and it improves the hardenability, weldability, and heat resistance of the steel. For example, stainless steels containing 4-5 per cent molybdenum are often used in places where erosion and corrosion are more severe, such as marine equipment and chemical equipment.

To molybdenum as a substrate by adding other elements (such as titanium, zirconium, hafnium, tungsten and rare earth elements, etc.) constitute non-ferrous alloys, these alloying elements not only molybdenum alloys play the role of solid solution strengthening and maintaining low-temperature plasticity, but also the formation of stable, diffuse distribution of carbide phases, to improve the strength of the alloy and recrystallisation temperature. Molybdenum-based alloys are used in high heating elements, extrusion grinding tools, glass melting furnace electrodes, spray coatings, metalworking tools, spacecraft parts and so on because of their good strength, mechanical stability and high ductility.