The synthetic mica does not contain hydroxyl (OH), its high temperature thermal stability is much higher than natural mica, muscovite mica decompose from 450℃, almost completely decomposed when temp over900℃. Phlogopite mica decompose from 750℃, weight loss significantly when temp over 900℃. So the max use temp for muscovite is 550℃ and phlogopite 800℃. But synthetic mica can be used till 1100℃, and only when temp is over 1200℃,synthetic mica will decompose itself slowly.
As synthetic mica is less impurities, better transparency, in addition to the hardness slightly larger than the natural mica, the other mechanical properties and electrical insulation properties or vacuum bleed performance all better than natural mica. So even synthetic mica cannot completely replace the natural mica, but it already show special performance as a better high temperature insulation materials.
STMAT developed good character synthetic mica machined parts with specially treatment to make it moisture proof and not stratified during complex outdoor environment, and still keep good electrical insulation performance, so our synthetic mica parts now can be applied into transmission resistor as insulation base substrate, it’s a good replacement of traditional stainless steel plate for grounding resistors. Nowadays this synthetic mica insulation plate already been accepted in the China State Grid HVDC（high-voltage direct current）Transmission Resistor project.