Molybdenum is a silver transition metal with a gray cast that does not occur naturally as a free metal on earth; it is found only in various oxidation states in minerals. Its melting point is the sixth highest among all elements. It easily forms hard, stable carbides in alloys. Therefore, most molybdenum products in the world (about 80%) are used as some kind of iron alloy, including high strength alloy and superalloys.
Molybdenum is mainly used in the steel industry. 0.3% molybdenum additive can improve the strength and corrosion resistance of cast iron in several steel types. Rust- and acid-resistant molybdenum steel alloys contain 0.4 to 3.5% molybdenum. Surface treatment can improve the mechanical strength of molybdenum-containing steel. Currently, molybdenum is also used in the production of heat-resistant superalloys.
The melting point of molybdenum is 2620 ° C. Due to the strong bonding between atoms; the strength is very high at room temperature and high temperature. It has a small expansion coefficient, large electrical conductivity, and good thermal conductivity. It does not react with hydrochloric acid, hydrofluoric acid and rhenium solution at normal temperature, and is only soluble in nitric acid, aqua regia or concentrated sulfuric acid. It is also quite stable to most liquid metal, non-metal slag and molten glass. Therefore, molybdenum and its alloys have a wide range of applications and good prospects in important sectors such as metallurgy, agriculture, electricity, chemical industry, environmental protection and aerospace, and have become an important raw material and irreplaceable strategic substance in the national economy. The application of molybdenum in the steel industry still occupies the most important position. As an alloying element of steel, it can improve the strength of steel, especially high temperature strength and toughness.