A novel in-situ β-Sialon/Si3N4 ceramic used for solar heat absorber. Issue 10 (December 2015)

• Record Type: Journal Article
• Authors: Wu, Jianfeng; Zhang, Yaxiang; Xu, Xiaohong; Lao, Xinbin; Li, Kun; Xu, Xiaoyang
• Is Part Of: Ceramics international. Volume 41:Issue 10(2015)Part B
• Page Start: 14440
• Page End: 14446
• Publication Date: 2015-12
• Subjects: A. Sintering -- B. Composites -- C. Thermal properties -- D. Nitrides -- E. Thermal applications; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.07.080
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: β-Sialon/Si3 N4 composites were fabricated via pressureless sintering method at 1580 °C using α-Si3 N4, calcined bauxite, AlN as the main raw materials, Y2 O3 and La2 O3 as the sintering additives. Mechanical properties, phase composition, microstructure, thermal shock resistance, oxidation resistance, thermophysical properties and solar absorptance were investigated. The results show that the sample with 3 wt% Y2 O3 and 3 wt% La2 O3 as additives exhibits the best mechanical properties, which also has high thermal conductivity and solar absorptance: 7.96 W/(m K) and 91.10%, respectively. The sample has intact morphology after 30 thermal shock cycles (wind cooling from 1100 °C to 25 °C), and the bending strength remains as high as 138.36 MPa. Its weight gain rate after oxidation at 1100 °C for 100 h is just 0.9331 mg/cm 2, which shows the excellent oxidation resistance. A dense oxide layer is found to be formed on the surface during the process which protects the sample from further oxidation. It is believed that this in-situ β-Sialon/Si3 N4 ceramic could be a promising candidate for solar heat absorbing material.