I found this page by also trying to find the name of this disc, which I too need to replace for use with my electric drill. I use it with a sanding disc rubber backing pad attachment, whereby I secure the disc to said attachment with a central screw and use it to sand very rough wood, where most paper and/or cloth type sanding discs would tear easily.
I have looked up the 'Tungsten carbide buffing disc' mentioned above and can find none that look like the disc I have been using for years, as they all seem to have a much wider central hole - 22.5mm instead of required 15mm and they are all about 6mm thick instead of being sheet metal.
After searching many alternatives I have finally tracked the correct disc down. It is a Cintride Abrasive Disc and a three disc set (Coarse, Medium & Fine) can be found on eBay (y-tools or M A Tooling shop) and I, personally, have ordered some today!
I hope the above is of some help. :-)