Enhanced Thermal Conductivity and Dielectric Performance of CMZBS–Glass–Ceramic Composites with AlN Whisker Incorporation for LTCC Applications

In this work, a small amount of AlN whiskers (ranging from 2 wt.% to 8 wt.%) was incorporated into CaO-MgO-ZnO-B₂O₃-SiO₂ (CMZBS)-glass/Al₂O₃ composites so as to obtain glass-ceramics with a thermally conductive network through sintering between 700 °C and 1000 °C. Special attention was given to the densification behavior, dielectric properties, and thermal conductivity of CMZBS/Al₂O₃/AlN-glass-ceramic composites with varying AlN whisker contents. According to the results, composites with desirable thermal, mechanical, and dielectrical properties were successfully fabricated. Notably, the composites containing 6 wt.% AlN whiskers, sintered at 800 °C, exhibited the most optimal comprehensive properties (dielectric constant of 7.06, dielectric loss of 383 × 10^-5, thermal expansion coefficient of 6.40·10^-6/K, flexural strength of 180 MPa, and thermal conductivity of 5.17 W/(m·K)). Given these attributes, this CMZBS/Al₂O₃/AlN composite holds great potential for applications in LTCC (low-temperature co-fired ceramic).