Dc bulk conductive ceramic with low rf and microwave loss

Abstract

A DC conductive, low RF/microwave loss titanium oxide ceramic provides, at room temperature, a bulk DC resistivity of less than 1×10ohm-meters and an RF loss tangent of less than 2×10at 7.5 GHz and less than 2×10at 650 MHz. The resistivity is reduced by oxygen vacancies and associated Tiand/or Ticenters created by sintering in an atmosphere containing only between 0.01% and 0.1% oxygen. The reduced resistivity prevents DC charge buildup, while the low loss tangent provides good RF/microwave transparency and low losses. The ceramic is suitable for forming RF windows, electron gun cathode insulators, dielectrics, and other components. An exemplary MgTiO—MgTiOembodiment includes mixing, grinding, pre-sintering in air, and pressing 99.95% pure MgO and TiOpowders, re-sintering in air at 1400° C.-1500° C. to reduce porosity, and sintering at 1350° C.-1450° C. for 4 hours in an 0.05% oxygen and 99.05% nitrogen atmosphere.