The 7000 series is more than enough for Apple’s durability needs. Common in construction, the 7000 series of aluminium alloys are among the strongest and least affected when subjected to extreme heat, not to mention that it is highly resistant to corrosion.
Moreover, this aluminium-zinc-manganese alloy is treated with trace amounts of manganese, chromium, and zirconium. Studies show that the zirconia coating in anodised aluminium alloys provide a significant level of protection from acidic corrosion. It was also proven that the coating reduces pitting corrosion, which had the reputation of being unpredictable.