Crystallization of low-k boron calcium silicate glass-ceramics induced by (3-CaSiO3 seed crystals

Calcium borosilicate (CBS) low temperature co-fired glass-ceramic substrates exhibit excellent dielectric properties in microwave wireless devices. Since the multiphase competition that occurs during the sintering of CBS glass-ceramics, achieving a high ratio of (3-CaSiO3 crystalline phases with dielectric properties is of critical importance. Here, by introducing varying levels of (3-CaSiO3 crystals as seed crystals, a highly crystalline (3-CaSiO3 phase was formed while achieving a dense glass-ceramic, and the crystal growth regulations were explored. Specifically, with a doping level of 3 wt% (3-CaSiO3, the glass-ceramics achieve optimal densification and a crystalline phase comprising 75 % (3-CaSiO3, with a low dielectric constant (5.03 at 1 MHz) and low dielectric loss (5.09 x 10-degrees at 1 MHz). The flexural strength exhibits 196.4 MPa. Moreover, the different crystallization stages, corresponding to various morphology crystal sizes, were identified. Our work presents a method for introducing seed crystals to induce spherical crystal growth in low-dielectric glass-ceramics.