Ceramic-polymer composites for microwave applications
Mikołaj Szafran, Barbara Bogdańska, Ewa Bobryk, Eugeniusz Jaszczyszyn, Krzysztof Derzakowski
Quarterly No. 1, 2012 pages 9-13
DOI:
keywords: ceramic-polymer composites, barium strontium titanate, aqueous tape casting, microwave frequency
abstract Ceramic-polymer composites with ferroelectric properties provide significant opportunities in the design and manufacture of modern electronic materials whose functional characteristics are constantly being improved. Barium titanate (BT) and barium strontium titanate (BST) are known and widely used materials in electronics. The paper presents the results of research on a receiving ceramic-polymer composite with an as low as possible permittivity and loss tangent. As a ceramic fraction barium-strontium titanate (BST) with various dopants (Fe2O3, Ni2O3, La2O3, SnO2 and Y2O3) were tested and as an organic one - water dispersions of styrene-acrylic polymers. The influence of BST doped with metal oxides on the sintering process was observed. X-ray diffraction patterns were made for sintered powders while the Vickers hardness, relative density and volume shrinkage of sintered pellets were studied. The zeta potential as a function of pH for pure BST and doped with Ni2O3 were measured. BST doped with Ni2O3 had the best relative density and this powder was used for further research. For the aqueous tape casting method four water dispersions of polymers with different concentrations and structures as binders were tested. For these polymers heat flow as a function of temperature by differential scanning calorimetry (DSC) and the glass transition temperature were measured. Additionally, the concentration of water dispersion of the polymers was tested by the gravimetric method. For the obtained ceramic - polymer composites, the relative permittivity and loss tangent were measured at a 9 GHz frequency.