Abstract:
Polytetrafluroethylene (PTFE)–Mg2SiO4 composites havebeenpreparedusingbothmicronandnano-ceramic fillers byhotpressing.The
dielectric propertiesofthecompositesareinvestigatedbothatradioandmicrowavefrequencyrangesasafunctionof filler loadingupto
50 vol%.Thedielectricconstantandlosstangentincreaseswith filler volumefraction.Thecompositewith50vol%micro-filler hasadielectric
constant of3.2andlosstangent0.009at5GHzwithVickersmicrohardness16HV.Thesurfaceofceramicparticleswasmodified bysilane
treatment. Thesurfacemodification reducedporosityandmoistureabsorptionandimprovedthemicrohardness.TheCTEofthecomposite
decreased andthermalconductivityincreasedwith filler loading.NanopowdersofMg2SiO4 has alsobeenpreparedbysol–gel methodand
composite hasbeenmadewithPTFE.Thenanocompositehashighermoistureabsorption,dielectricconstantandlosstangentbutlowerCTE
value. ThePTFE–Mg2SiO4 composites arepossiblecandidateformicrowavesubstratesapplications
