Tungsten is a heavy metal exhibits the highest melting point among all the refractory metals. The pure tungsten has a yield strength of 750 MPa and excellent tensile strength of 900 MPa. Due to its amazing strength and hardness, tungsten was widely applied in various fields include defense industry, aerospace industry, and nuclear industry. The conventional alloying method by combining tungsten with other metals is a proven efficient route to enhance its properties to extend its applications.

Tungsten copper composite material is widely used to produce electrical contact.

The emergence of quaternary-compound tungsten electrode, which also called WX4, marks a new area of tungsten electrode material, as well as a revolutionary development of the relevant technology, making the reliability and stability of the electrodes further improved. In 2017, based on the Tri-mix composite rare earth technology, China’s researchers continued to break through the technical barriers and are the first one to add four kinds of different rare earths to tungsten, e.g. lanthanum, cerium, zirconium, and yttrium.  

Vanadium dioxide (VO2) is widely applied in the fields of intelligent energy windows coating, optical switching devices, optical data storage medium, electrodes for electrochromic, lithium batteries and supercapacitors. VO2is a reversible first-order metal-insulator transition (MIT) at a critical temperature (Tc). VO2 is a monoclinic structure (M), and presents semiconductive and relatively infrared transparent below Tc, whereas it transforms into tetragonal structure (R), and presents metallic and infrared reflection above Tc. However, the high critical transition temperature of VO2 material (about 68 °C) limits its application.