Pure Nickel 200 Pipe Pure nickel (alloy 200) has very good corrosion resistance to a wide range of reducing acids and salts, but is not suitable for conditions with strong oxidizing properties, such as nitric acid. The most significant property of pure nickel is that it is not resistant to strong alkalis, especially when strong bases are in a molten state. Although the corrosion resistance to dry halogen environments is outstanding, nickel is not suitable for environments below the dew point of water. For use in environments above 6000F, it is best to choose a low-carbon grade, codenamed Nickel 201 (UNS N02201).