Process for making improved microwave susceptor comprising a dielectric silicate foam substance coated with a microwave active coating

A process for making a dry dielectric silicate foamed microwave susceptor comprising the following steps:

• a) preparing pourable aqueous alkali metal dielectric silicate slurry;
• b) pouring said slurry into a smooth surface substrate mold;
• c) heating said poured slurry at an effective elevated temperature to foam the slurry in said mold;
• d) drying said foam at an effective elevated temperature to provide a dry dielectric silicate foam substrate having a moisture level of from 0% to 5%, by weight of dry foam, and having at least one substantially smooth surface;
• e) coating at least a portion of said substantially smooth surface with a flowable microwave active coating, said microwave active coating comprising an alkali metal silicate binder and a microwave active constituent;
• and
• f) drying said flowable coating at an effective temperature to form a dry microwave active coating layer and wherein said dry layer of microwave active coating has a surface concentration of said active constituent of at least about 1.0 gram per square meter.