The experimental work over the past two years consisted of three steps.
The first step centred on the development of bulk capacitor ceramics with high capacitance/dielectric constant to be used as reference materials.
The second step centred on the development of high surface area ceramics with improved charge storage capabilities.
The third step will centre on the development dielectric films on metal substrate with good adherence to the metal substrate and possessing no pitting or discontinuities responsible for decrease in capacitance. We will use a novel ultrasound technology for mixing and grain refinement.
The powder was pressed and fired at various temperatures ranging to produce dense non-porous samples.The samples were then electroded and tested for capacitance (C), dielectric constant (K), dielectric loss (loss tan) and temperature coefficient of capacitance (TCC).
A Significantly higher dielectric constant was achieved with samples as shown in Fig. 1 at the left. (Click image to enlarge).
A high surface area is important to prevent electric run away. Extensive work has already been done.
After sintering surface uniformity and thickness of the films were observed under the Optical and Electron Microscopes. No defects were observed and the thickness of the films varied from 10 to 100 microns.
The increase in dielectric constant with sintering temperature is believed to be associated with the increase in film density and in the improvement in film adherence/bonding to the metal electrodes.