Effects of isothermal annealing on the oxidation behavior, mechanical and thermal properties of AlN ceramics. Issue 12 (15th August 2017)

• Record Type: Journal Article
• Authors: Cao, Changwei; Feng, Yongbao; Qiu, Tai; Yang, Jian; Li, Xiaoyun; Liang, Tian; Li, Jun
• Is Part Of: Ceramics international. Volume 43:Issue 12(2017)
• Page Start: 9334
• Page End: 9342
• Publication Date: 2017-08-15
• Subjects: AlN -- Isothermal oxidation -- TGA-MS -- Mechanical property -- Thermal conductivity; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2017.04.098
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: To evaluate the oxidation behavior of AlN ceramics prepared using a pressureless sintering method, aluminum nitride bulk samples were annealed at temperatures ranging from 900 °C to 1300 °C for 1–5 h under an air atmosphere. The phase composition, microstructure and weight change of the oxidized samples were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis-mass spectrometry (TGA-MS), respectively. The results showed that certain of the gaseous oxidation products of AlN ceramics were nitrogen oxides (NOx ). The oxidation reaction started at approximately 800 °C to 900 °C. The thermal conductivity and flexural strength of AlN ceramics were enhanced slightly after the heat treatment in the 900–1100 °C temperature range. The entire surface of the AlN block was covered with a thin, compact alumina layer after oxidizing at 1100 °C for 3 h, which may enhance the metal adhesion to the AlN surface in a metallization process. At 1200 °C and higher, the AlN ceramics oxide layer became rough, porous, and cracked, leading to a sharp drop in the flexural strength and thermal conductivity of the AlN ceramics.