Sarcasm is the use of irony (which involves opposites) in order to ridicule something or be funny*. An event or situation itself cannot be sarcastic, but people and the things they say can.
I -and many other folks- would call your situation of having bought an album titled Scratch only to find the CD was itself scratched to be "ironic". Although it is possible to make a case that technically it is only an unfortunate coincidence, I would defend my use by pointing out that the expected state of any new CD is pristine. It's not a strong argument but the exact definition of irony is hard to pin down.
Now if you took the album back to the store for a refund and the clerk looked at you and said, "You bought an album named 'Scratch', what did you expect?" that would be considered sarcastic!
*controversal. Some of us are just lazy and misuse both the word (by calling coincidece irony) and the concept (by making jokes we shouldn't).