Nickel is a silver-white ferromagnetic metal. Density 8.9g / cm ~ 3, melting point 1455 ℃. Ancient Egypt, China, and Babylonians used high nickel-rich meteor iron as utensils. It can be said that nickel is both "old" and "young" metal. Nickel is magnetic and is the main component of many magnetic materials. Nickel also has good oxidation resistance, in the air, nickel surface formation of NiO film, can prevent further oxidation. It has been proved that nickel with purity of 99% will not occur rust mark within 20 years. Nickel has a strong corrosion resistance, especially against caustic soda, which is dissolved in 50% boiling caustic soda. The annual corrosion rate of nickel in the liquid is not more than 25 microns. Nickel strength and plasticity are also good, can withstand a variety of pressure processing. 

At present, nickel raw materials are mainly nickel sulphide ore, followed by oxide ore. In addition, manganese nodules in the sea floor will also become an important resource for nickel extraction. Nickel is widely used to make various types of stainless steel, soft magnetic alloys and alloyed structural steels. Nickel and chromium, copper, aluminum, cobalt and other elements can constitute heat-resistant alloys, electrical alloys and corrosion-resistant alloys. A thermoelectric (resistance wire) made of a nickel-chromium alloy (such as Ni- Cr20) that has a high heat resistance and resistance, and can be used as an electric furnace, electric iron, etc. Ni-Cr9 and Ni- Cr10 can work at 1100 ℃ for a long time, but the resistance is large, the temperature coefficient of resistance is small and the thermoelectric potential is large, so they are good materials for thermocouple.