Effects of two-step sintering on thermal and mechanical properties of aluminum nitride ceramics by impedance spectroscopy analysis. Issue 2 (February 2019)

• Record Type: Journal Article
• Authors: Jiang, Hai; Wang, Xiao-Hong; Lei, Wen; Fan, Gui-Fen; Lu, Wen-Zhong
• Is Part Of: Journal of the European Ceramic Society. Volume 39:Issue 2/3(2019)
• Page Start: 249
• Page End: 254
• Publication Date: 2019-02
• Subjects: Aluminum nitride (AlN) -- Thermal conductivity -- Mechanical property -- Two-step sintering -- Impedance spectroscopy; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2018.09.026
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: The effects of two-step sintering on the microstructure, mechanical and thermal properties of aluminum nitride ceramics with Yb2 O3 and YbF3 additives were investigated. AlN samples prepared using different sintering methods achieved almost full density with the addition of Yb2 O3 –YbF3 . Compared with the one-step sintering, the grain sizes of AlN ceramics prepared by the two-step sintering were limited, and the higher flexural strength and the larger thermal conductivity were obtained. Moreover, the electrochemical impedance spectroscopy of AlN ceramic was associated with thermal conductivity by analyzing the defects and impurities in AlN ceramics. The fitting grain resistance and the activation energy for the grain revealed the lower concentrations of aluminum vacancy in the two-step sintered AlN ceramics, which resulted in the higher thermal conductivity. Thus, mechanical and thermal properties for AlN ceramics were improved with Yb2 O3 and YbF3 additives sintered using two-step regimes.