Abstract: The xCuO-(22.2-x)MgO-22.2Al₂O₃-55.6SiO₂ (x=0, 0.25, 0.50, 0.75 and 1.00, molar fraction) (MAS) glass-ceramics were synthesized using sintering-crystallization method. The effect of CuO content on the crystallization behavior, crystal type, micromorphology and microwave dielectric properties of MAS glass-ceramics was studied. The results show that as the CuO content increases from 0% to 1.00%, substituting for MgO, the glass transition temperature decreases. Additionally, the precipitation peak temperatures also show a decreasing trend, while the Avrami index n gradually increases. The primary crystalline phase in glass-ceramics is α-cordierite. The inclusion of CuO facilitates the transformation of μ-cordierite to α-cordierite at lower temperatures and reduces the thermal expansion coefficient. With the increase of CuO content, the dielectric constant of glass-ceramics increases first and then decreases, while the dielectric loss decreases first and then increases. At a heat treatment 650 ℃/2 h+1 050 ℃/2 h, the glass-ceramics doped with 0.25% and 0.50% CuO exhibits optimal integrated dielectric properties, which dielectric constant is 5.04 and 5.07, dielectric loss is 7.49×10^-4 and 7.12×10^-4, and quality factor is 20 013.35 and 20 786.41 GHz within the frequency range of 14.6~15.2 GHz.

Key words: cordierite glass-ceramics, CuO, sintering-crystallization method, microwave dielectric property, crystallization kinetic