ToughSF @ToughSf
The F-22 is coated with radar-absorbent materials in Polymer Matrix Composites. Max operating temperature is ~300°C.
The Mach numbers, limited by skin temperature, are Mach 2.5 at 6 km altitude, up to Mach 2.8 at 11 km.
It cannot be much faster than the F-15 despite more thrust.