Performance comparison between pure nickel and copper nickel alloy
Nickel alloy is widely used in desulfurization industry. The main reason is that it has strong acid resistance and strong corrosion resistance to halogen ions. The corrosion resistance of various nickel alloy materials varies with the content of alloy elements.
The passivation protection of nickel copper alloy is improved due to the addition of a small amount of copper. The nickel content in the alloy is very high, and its corrosion resistance is equivalent to that of pure nickel.
This kind of alloy can be widely used in high-speed flow and erosion prone parts, such as screw shaft, propeller, impeller pump blade, condensate contact, and sulfuric acid solution.
The alloy has strong corrosion resistance to different concentrations at various temperatures, and its corrosion rate is 0.05 mm / A or less in vacuum. At 100 ℃, it shows strong corrosion resistance in 30% solution. Stress corrosion cracks can be observed in ventilated high-temperature solution, which can be solved by pumping out medium gas or stress relief annealing of equipment.
There is only slight corrosion in neutral and alkaline solutions (such as chlorate, carbonate, sulfate, salt and acetate) at high concentration and boiling point. Therefore, this alloy can be used to make containers for producing crystals from saturated brine. They are also widely used in steam equipment and crystallization vessels. But the salts of oxidizing acids and some basic salts are harmful to them
Strong corrosion, such as hypochlorite.
For NaOH and KOH solutions, the alloy has strong corrosion resistance similar to pure nickel. At 130 ℃, the corrosion rate is only 0.05mm/a or lower in 75% alkali solution; In 75% NaOH or anhydrous NaOH, the corrosion rate is higher than that of pure nickel, and stress corrosion cracks can be seen in molten NaOH for parts subject to severe mechanical extrusion. Therefore, for the parts used under these working conditions, the material can be stress relieved annealed or pure nickel can be used.