That was another hotly (zing!) contested item. Would altering the thermal dispersion properties of inconel/stainless increase or decrease the lifespan/strength/resilience.
Aviation seems to attract engineers from all disciplines, but damned if I can find a thread where a metallurgist has weighed in on ceramic coating aviation exhausts.
There's no doubt that inconel holds up better than stainless for an exhaust. This is the whole reason why the turbo Twin Cessnas use inconel. I'm not sure what the turbo Lycomings use, but pretty sure they also use inconel. The positive about this is that it holds up to the higher temps, the negative is that it costs a ton of money. Turbo Twin Cessnas have an AD on the inconel exhaust because, even then, there are various longevity issues.
In the turbine engine world, inconel (and other highly expensive metals) are used all over for their thermal properties. Ceramics have also made their way into various parts, but using parts made out of ceramic altogether, rather than just coatings like we're talking about here. I'm sure there are ceramic coatings used in some places as well.
If you think about it, the ceramic coating is mainly supposed to provide a layer of insulation to the metal to prevent it from reaching the full temperature of the exhaust gasses. In other automotive realms, there have been ceramic coatings advertised for pistons, valves, combustion chambers, etc. for basically the same purpose - keep as much of the heat in the combustion chamber as possible, which increases power/efficiency and also decreases the load on the cooling system.
You would to consider bonding capabilities. I don't know about how the ceramics would bond to inconel in comparison to aluminum, stainless, etc.
Not much in relative terms...car guys don't usually think about AMU's.
Right, but when you're talking $10k/side for an exhaust, adding another $1-2k is still significant unless you can determine there is a benefit. That said, I'd be all for trying it on the 414 if there was a legal way to do so.