One problem in induction heating is that energy is lost because the object being heated radiates energy, that energy then heats the coils (which are water cooled) and the coils suck away the energy.
One idea is to insulate the object being heated. For example, a thin-walled cylinder of polished tungsten could be placed between the object being heated and the coil. This will reflect some of the infrared energy being emitted from the object and reduce the heat loss. Another potential material is gold. So, for example, silica plated with the gold might be a possible. The issue with gold is that it is a good infrared reflector, but it melts at 1400C and the object can reach that temperature, so it would be at a borderline temperature for melting. Also, gold is not paramagnetic.
The problem with this idea is that tungsten is paramagnetic so it will absorb some of the energy from the coil.
How can I compute whether using a tungsten cylinder reflector would have a net benefit without doing an actual experiment?