I am experimenting with some widely known microwave susceptors like iron oxide and silicon carbide (materials that normally convert RF to heat quite effectively). In ceramic formulations they perform great, as expected. When formulated in silicone rubber, they do not perform when subjected to identical watts/time in a home microwave, almost nothing. I am seeing less than 1/2 the temperature rise per time in the silicone matrix. Curious if the good performance of these materials in dry ceramic form could be due to the resonance or vibration of these materials in and against the dry ceramic matrix, and against each other (very frictional) - - and in silicone rubber the medium is rather viscoelastic, so more of the vibrational energy is absorbed by the flexible nature of the medium.