Depends! Most powder coatings are comprised of polymers that melt at 450F or less. Dry powder is electrostatically applied to the object and then the object travels through a furnace that melts the plastic powder so that it wets the surface, smoothens out to an even layer and then solidifies as the temperature falls below its melting point as it leaves the furnace. These coatings can take about the same heat they were baked at before they are damaged. They are tough, elastic and very good at protecting the substrate.
Other powders made from metals such as powdered aluminum can take higher heat up to the melting point again so about 900F or thereabout. To have even higher heat resistance requires ceramic powders, such as glass or silicones, or other materials that have melting temps as high as 2,300F. These are similar to porcelain in some respects.
The question to ask a potential coating vendor is this: How high is the temperature of your baking ovens? The answer will tell you how much heat their coatings can likely take. Jet Hot brand "chrome" is as good as I have found. To be really effective exhaust pipes are coated inside and out. The inside coating acts as both a thermal barrier and a reflector reducing the heat that gets to the metal. There are likely some others equally good, but a whole bunch that are crap despite the advertising otherwise.
Exhaust headers can reach 1,400F if un-covered and way higher if under heat shields. That dull red you may have seen on the stock exhaust is about 1,100F. The color turns to bright cherry at 1,400F and then orange at about 1,650F.
Sprayed on liquid coatings by definition are not powder coatings, although some contain metal or silicone particles in suspension and can survive exhaust manifold temperatures, but only for a while before they whiten and lose color. After that they reduce to ash, flake off, and leave the under lying metal exposed.
Outer heat shields might survive with a powder coating but that would depend on their proximity to the underlying pipe.
