A low-cost (Mg_(1-x)Ca_x)_3B_2O_6 (0 ≤ x ≤ 1.0 mol.%) ceramic with enhanced microwave dielectric properties

摘要

A low-cost (Mg_(1-x)Ca_x)_3B_2O_6 (0 ≤ x ≤1.0 mol.%) (MC_XB) microwave dielectric ceramic was prepared by solid-state method. X-ray diffraction, scanning electron microscope, and vector network analyzer were adopted to characterize the phase composition, microstructure, and microwave dielectric properties of the as-fabricated MC_xB ceramics. All the MC_xB (x = 0-1.0 mol.%) ceramic samples exhibit the singe orthorhombic structure corresponding to Mg_3B_2O_6 (JCPDS 75-1807). Excellent microwave dielectric properties (ε_r = 6.8, Q × f = 103,556 GHz, τ_f=- 34.5 ppm/°C at 12.6 GHz) were obtained in the MC_(0.002)B (x = 0.2 mol.%) ceramic sintered at 1250 °C for 3 h, making it a prospective candidate for the practical application in portable terminal and wireless communications.