There are a few different manufacturers of RV awnings; ZipDee, Carefree, and A&E to name the most common.
Here is an example of the various parts for an A&E 9000:
I have found this to be a good on-line source for RV parts:
PPL Awning Parts CatalogThey will also help you over the phone, if you prefer.
It would help us on the forum if you could provide a picture of the part and or the make and model of the awning. I have broken and replaced parts on my awning, but not a black one like you described.
I hope this helps...
Jim