The effects of firing temperature and test frequency on dielectric properties such as dielectric constant, dielectric loss of three conductor-dielectric (combination) samples, namely nickel-cordierite, silver-cordierite and titanium cordierite samples have been studied after firing. The results showed that the value of dielectric constant and dielectric loss decreased with increasing test frequencies and increasing firing temperature such as 700degreesC at 1 MHz. A dielectric constant as low as 2.2 was obtained for the nickel-cordierite samples. In addition, the samples were also analyzed for phase purity and phase transformation with an X-ray diffractometer (XRD). Though XRD can detect presence of a phase only beyond 1%, it was used to determine the extent of diffusion of conductor ions across the interface. There could have been a small diffusion of the conductor ions, namely nickel, silver and titanium into the cordierite during firing, but it was not detectable, so presumably the diffusion had produced less than 1% of the total amount of phases in the fired samples. (C) 2003 Kluwer Academic Publishers.