Does This 1985-D Have A Double D?

Looks like Die Deterioration

Split plating, the zinc is exposed and beginning to corrode.

No, it's not.

Split plating is where the copper plating splits open like a cut when the coin is struck leaving the sinc core exposed to the elements. The zinc rots and hollows out underneath the copper shell leaving a cavity.

Die Deterioration is when a die strikes so many coins it starts to lose its detail. The loss of detail transfers to the coin as blurry details, deep and long flow lines, etc.

The two terms are very different.

The coin in this thread is split plating.

Just two minor anecdotes to add to this...and they are related.

Mintmarks were placed into the individual cent dies by hand until (and including) 1989. The integrity of the very thin copper plating on the planchets depended heavily on the design having the proper 'bevel' so the devices would not get stuck in the recesses of the die. Given that the mintmarks were placed by hand, many times they were tilted slightly so as to create a shearing edge along the mintmark. This is why the zinc is most often exposed around the mintmark.

Second thing, I agree with chugly except to say that the zinc cents up to 1990 are the ones that rot will take the best of because of the split plating issue. Any zinc cent 1982-1989 in nice uncirculated grades will eventually be the comparison to the Indian Head cents of the 1870s (but for different reasons). The comparison is that basically there will be a stretch in the middle of the series where values will be way higher than on either side. My forecast is that this section will be 1982-1989.