Tailoring microwave-millimeter-wave dielectric and mechanical properties in CaO–SiO2 glass-ceramics by P2O5 nucleating agent

Abstract

Glass-ceramics have demonstrated excellent dielectric properties in low-temperature co-fired ceramic (LTCC) technology used in 5G/6G wireless devices. This work studies the mechanical strengths and dielectric properties from microwave to millimeter-wave frequencies in the CaO–SiO2 glass-ceramics modified via the P2O5 as a nucleating agent. The β-wollastonite phase was identified as the primary structure with the preferred (202‾) orientation and parallel plate-like structure in the matrix as P2O5 content increases up to 3.5∼5.5 wt%. The P2O5 nucleating agent increases degree of long-range crystallization. Elevated mechanical flexural strength of approximately 170 MPa, hardness of ∼720 MPa, and outstanding high-frequency dielectric properties were obtained in the 3.5–5.5 wt% P2O5-added CaO–SiO2 glass-ceramics, due to the enhanced interatomic Si–O bonding in the network. The improved mechanical and dielectric characteristics of the P2O5–added CaO–SiO2 glass-ceramics make the crystallized wollastonite materials for the 5G/6G devices possible.