resumo
Herein, an innovative two-step method was proposed to prepare dense spherical aluminum nitride (AlN) fillers for the application of insulating encapsulants, involving spray granulation from AlN-based suspensions and subsequent sintering process to achieve full density. According to investigations on the dispersing ability of powders, the AlN-based aqueous suspensions with various solid loading were firstly prepared for spray granulation. It was indicated that a low-viscosity and high-concentration suspension could enhance the sphericity and uniformity of green granules and simultaneously facilitate the high green density. The spherical AlN green granules were further sintered with boron nitride (BN) powders, which played a role as the interval material to retain the spherical morphology and hinder the agglomerations of AlN granules. The distinct impacts of BN powders, sintering temperatures and additive species on the overall properties of resultant AlN fillers were further studied and rationally uncovered. Based on these results, spherical AlN granules with superior dispersion, low porosity and an average particle size of more than 40 gm were successfully fabricated via the newly-developed two-step method, showing promising potentiality for the application as thermal conductive fillers.
palavras-chave
ENHANCED THERMAL-CONDUCTIVITY; REDUCTION-NITRIDATION METHOD; ALUMINUM NITRIDE; CERAMICS; COMPOSITES; GRANULES; GRAPHENE; BEHAVIOR; POWDERS; EPOXY
categoria
Materials Science
autores
Wang, Q; Ge, YY; Sun, SY; Kuang, JL; Ferreira, JMF; Cao, WB
nossos autores
José Maria da Fonte Ferreira
Professor(a) Jubilado(a)agradecimentos
The study was financially supported by National Natural Science Foundation of China (No. 51602017), China Postdoctoral Science Foundation (No. 2015M580044), Fundamental Research Funds for the Central Universities (No. 2302015FRF-TP-15-079A1) and State Key Laboratory of New Ceramic and Fine Processing Tsinghua University (No. KF201617).