Recently picked up a "ceramic" coated frying pan for the first time and wondering what it's actually made of and how it's put on.

From the color I'm guessing alumina or maybe silica is likely? Sintered powder coating then firing? My first inclination for putting such a layer on something would be CVD but that's probably too expensive for the thicknesses and production volumes in question, but I feel like a sintered powder layer would be too porous.