Effect of Al content on corrosion resistance of Cu-22.7Zn-Al-1.0Ni brass

Study the effect of aluminum content (2.0%, 2.5% and 3.0%) to characteristics of Cu-22.7Zn-Al-1.0 Ni alloy such as as-cast, hot-rolled and cold-rolled strip. The results show that: The shape and size of grains changed with Al content change. With the increase of Al content in the alloy, the size of α phase decrease evidently, the shape of α phase changes from block to strip and distributed more uniform. The hardness and corrosion resistance of alloy enhanced with the increase of Al content in the alloy, but the elongation decrease with the increment of Al. When the content of Al changes from 2.0% to 3.0%, the deepest corrosion depth of alloy as-cast, hot-rolled plate and cold-rolled strip drop from about 140μm to 118μm, 68μm to 57μm and 103μm to 88μm respectively, those samples are corroded in the 1%CuCl₂ solution at 75 °C for 24 hours. Corrosion resistance of hot-rolled plate is better than as-cast alloy, the strip after annealed is better than cold-rolled strip.