Processing and Characterization of Aluminum Nitride Ceramics for High Thermal Conductivity

Abstract

The effects of sintering additives, microstructure, and morphology of second phase on the thermal conductivity of aluminum nitride ceramics are discussed in this review. The thermal conductivity of AlN is highly dependent on the types and amount of sintering additives, second phase morphology and microstructure. The morphology of second phase in AlN ceramics could be controlled by changing the cooling rate. The amount of second phase was able to be minimized by using the transient sintering additives. The thermal conductivity of AlN could be enhanced with the inclusion of the transient sintering additives. The thermal conductivity of AlN ceramics was evaluated by Raman spectroscopy. High temperature AC impedance studies were conducted to characterize the electrical conduction mechanism of AlN ceramics.

Fabrication of Al2O3/AlN micro-composites designed for tailored physical properties

“…Particles sizes were controlled to provide a large difference in the surface areas (particle sizes: AlN about 50 μm, Al 2 O 3 about 2~5 μm). The normal sintering temperature for AlN (> 1700℃) is much higher than that of Al 2 O 3 (1400-1600℃) [17][18][19][20][21]. The thickness of the interdiffusion layer in the final stage of sintering can be minimized when the composite is sintered at 1400℃…”

Gel-tape-casting of aluminum nitride ceramics

“…[12]). As we know, the thermal conductivity of AlN ceramics is affected by the low thermal conductive second phases segregated in grain boundary, including the morphology and microstructure of the second phases [16]. From the microstructure and EDS analysis (Figs.…”

Influence of Transient Liquid Phase Promoting Additives upon Reactive Plasma Spraying of AlN Coatings and Its Properties

“…Using sintering aids is considered to be the most common solution to eliminate the pore and oxygen related defects in AlN ceramic industries. Generally, densification of AlN is achieved by using rare earth oxides, alkaline earth oxides or mixtures, and using Y 2 O 3 and CaO are considered to be the most common for AlN sintering . Therefore, this paper will focus on investigating the feasibility of introducing a sintering agent for the fabrication of AlN coatings and its influence on the phase formation and coating microstructure during reactive plasma spraying.…”