Fabrication and characterization of glass-ceramics doped with rare earth oxide and heavy metal oxide

Cordierite-based glass-ceramics with non-stoichiometric composition doped with rare earth oxide (REO2) and heavy metal oxide (M2O3) respectively were fabricated from glass powders. After sintering and crystallization heat treatment, various physical properties, including compact density and apparent porosity, were examined to evaluate the sintering behavior of cordierite-based glass-ceramics. Results show that the additives both heavy metal oxide and rare earth oxide promote the sintering and lower the phase temperature from mu- to alpha-cordierite as well as affect the dielectric properties of sintered glass-ceramics. The complete-densification temperature for samples is as low as 900 degreesC. The materials have a low dielectric constant (approximate to5), a low thermal expansion coefficient ((2.80 similar to 3.52) x 10(-6) degreesC(-1)) and a low dissipation factor (less than or equal to0.2%) and can be co-fired with high conductivity metals such as Au, Cu, Ag/Pd paste at low temperature (below 950 degreesC), which makes it to be a promising material for low-temperature co-fired ceramic substrates.