Phase composition, bond characteristics and thermal conductivity of novel Cu4O(PO4)2 microwave dielectric ceramic at low sintering temperature

The Cu 4 O(PO 4 ) 2 ceramic with triclinic structure (P-1) was successfully synthesized by hydrothermal and solid-phase reaction process. The influence of the relative density on the dielectric properties and thermal conductivity was systematically investigated. The crystal structure parameters of Cu 4 O(PO 4 ) 2 ceramics were determined using GSASⅡ software. Based on the P-V-L theory, it is discussed that the dielectric constant of Cu 4 O(PO 4 ) 2 ceramics is predominantly influenced by the bond ionicity ( f i ) of Cu-O, and the quality factor is significantly affected the P-O strongly. Concurrently, the P-O bond plays a positive role in the temperature coefficient of the resonance frequency while the Cu-O bond plays a negative role. The quality factor of Cu 4 O(PO 4 ) 2 ceramic sintered at 850 °C is 23,029 GHz, the dielectric constant is 7.54, and the temperature coefficient of resonance frequency is −103.44 ppm/°C. At the same time, the thermal conductivity of Cu 4 O(PO 4 ) 2 ceramic sheet is 0.42 W/(m∙K). The research on Cu 4 O(PO 4 ) 2 ceramic contributes to establishing a new material system for the field of low temperature co-fired ceramics.