I found this stuff while surfing. Says it is good before power coating
Hi-Temp Lab-metal must be baked at 425 deg F for an hour and then is good up to 1000 deg F.
Then there is
Lab Metal which is good up to 425 deg F and looks like it requires no heat curing. 51% atomized aluminum powder so it must be conductive.
Fastenal carries it
Lab-Metal 20oz tube for $27.19
Tom