Molybdenum is refractory rare metals. The melting point is 2620℃. Because of the strong atomic binding force, the strength is very high at room temperature and high temperature. It has small expansion coefficient, large electrical conductivity and good thermal conductivity. It does not react with hydrochloric acid, hydrofluoric acid and alkali solution at room temperature. It is only soluble in nitric acid, aqua regia or concentrated sulfuric acid. It is also quite stable to most liquid metals, non-metallic slag and molten glass. Therefore, Molybdenum and its alloys have been widely used in metallurgy, agriculture, electrical, chemical, environmental protection and aerospace industries.