N4 pure nickel shows good corrosion resistance in many acidic and alkaline environments and is mostly used in reducing media. Nickel is characterized by the corrosion resistance of alkaline media, such as caustic potash, caustic soda, etc., so it is widely used in the process of ionic film caustic soda. Compared with most alloys, nickel has good corrosion resistance in dry fluorine. Nickel has also been successfully used in dry chlorine gas from room temperature to 540°C. N4 is a pure commercial nickel with a very low carbon content that is approved for use in services up to 1230°C. Nickel has good mechanical properties in a relatively wide temperature range, and is easy to cold work. Its processing characteristics are similar to those of low carbon steel.