Study of copper substitutions in Ag(NbxTa1-x)O3 solid solutions

The effect of copper in AgNb1-xTaxO3 solid solutions (ANT) was studied. Firstly, CuO was added after calcination and used as a sintering aid. Secondly, copper oxide was introduced as a raw material by substituting part of Ag2O, Nb2O5 or Ta2O5. Compositions were made using a conventional ceramics route. The powder processing and the firing conditions were optimised. For all the formulations, silver precipitates were observed inside the ceramics. The lowest dielectric losses were obtained for Ag2O deficient samples sintered at 915 C in an oxygen atmosphere. With a permittivity of 415 and a Qxf = 610 GHz, these compositions exhibited better dielectric properties than CuO added samples. These characteristics are very promising for filtering applications in the radio-frequency range. 4 refs.