Performance comparison of pure nickel and copper-nickel alloy materials
Nickel alloy materials are widely used in the 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 alloying elements.
Due to the addition of a small amount of copper, the passivation protection of nickel is improved. The nickel content in this alloy is very high, and its corrosion resistance is comparable to pure nickel.
These alloys can be widely used in high-speed flow and erosion-prone parts, such as screw shafts, propellers, impeller pump blades, condensate gas contact, and can also be used in sulfuric acid solutions.
The alloy has strong corrosion resistance to different concentrations at various temperatures, and its corrosion rate is 0. 05mm / a or less under vacuum. At 100 ℃, it shows strong corrosion resistance in 30% solution. In ventilated high temperature solutions, stress corrosion cracking can be observed, which can be achieved by pumping out the medium gas or annealing the 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 crystal production from saturated brine. They are also widely used in steaming plants and crystallization vessels. But salts of oxidizing acids and some basic salts have a significant impact on them.
Strong corrosive effect, 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 subjected to severe mechanical extrusion. Therefore, the parts used under these conditions can be stress-relief annealed or pure nickel.