Excuse me, how long can the salt spray time last without surface treatment of brass?

After salt spray test of nickel plating on brass, the reason of abnormal surface color of the material is 1, and the porosity of the coating is high. In fact, the abnormal place is that the salt water corrodes the substrate and the corrosion products crystallize. 2. The coating density is not enough, and the salt water corrosion produces shadows. 3. Sodium chloride itself is corrosive to nickel. 4. When the concentration of brightener in the solution is too high, the mixed product of corrosion coating and organic brightener will crystallize. Brass is an alloy of copper and zinc. Brass composed of copper and zinc is called ordinary brass. Brass is usually used to make connecting pipes for valves, water pipes, air conditioners and radiators.