Investigation on low‐temperature sintered AlN nanoceramics with high thermal conductivity

Abstract

The aim of this research was to investigate the effect of sintering additive and relatively low‐sintering temperature on the thermal conductivity of aluminum nitride nanoceramic. While using nanosized AlN powder and liquid‐phase sintering additives, the various sintering processes were performed at temperatures 1400 and 1500°C for several hours. In the analysis methods, thermal conductivity (K) and thermal diffusivity (α) were measured using thermal conductivity analyzer (Hot Disk), scanning electron microscope (SEM) was used to observe the surface morphology of the microstructure, x‐ray diffraction analyzer (XRD) to analyze the grain size and crystal structure, Raman spectroscopy (Raman) emission spectrum was analyzed to identify the material microstructure and the densities of AlN specimens were measured by Archimedes method. It was found that the thermal conductivity is related to the densification of nanosize low‐temperature sintered material, which can be controlled by additives and sintering temperature. With Y2O3 sintering add, the densification of AlN for low‐temperature sintering increased by the factor of ～5% to ～12%, and the thermal conductivity was enhanced by 25%. The relative density observed in this research is about 78%‐84%, and the thermal conductivity measured is in the range of 9‐14 W/mK.

Heat dissipation in 3D printed cellular aluminum nitride structures

“…The AlN ceramic powder composition was prepared by powder mixing 97 wt.% of AlN (Grade C, H.C. Starck GmbH, particle size in the range of 0.8-2.0 µm) and 3 wt.% of Y 2 O 3 (Grade C, H.C. Starck GmbH, mean particle size d 50 = 0.9 µm). The Y 2 O 3 content was selected because it promotes the densification of AlN and captures oxygen from the ceramic lattice, which, therefore, contributes to increase the thermal conductivity [17,18]. The powder composition was homogenized by ball milling (polytetrafluoroethylene balls) in isopropyl alcohol media for 90 min.…”

Effect of Ni foam on the microstructure and properties of AlN ceramic/Cu brazed joint

“…AlN ceramics have gradually attracted the attention of many experts because of its good thermal conductivity and stability. [6][7][8][9] However, the poor workability of AlN limits its applications in connection with metal. [10][11] To solve these problems, some methods were applied for connection between ceramic and metal such as solid-phase diffusion welding, [12][13][14] liquid-phase diffusion welding 15 and brazing.…”

“…Ceramic clad copper has become the first choice of ceramic lining plate in IGBT module packaging. AlN ceramics have gradually attracted the attention of many experts because of its good thermal conductivity and stability 6–9 . However, the poor workability of AlN limits its applications in connection with metal 10–11 .…”