Phase relations in the Si–Al–Gd–O–C system. Issue 2 (1st February 2016)

• Record Type: Journal Article
• Authors: Wei, Zhenbang; Jiang, Yong; Liu, Limeng; Wu, Laner; Huang, Zhenkun
• Is Part Of: Ceramics international. Volume 42:Issue 2:Part A(2016)
• Page Start: 2605
• Page End: 2610
• Publication Date: 2016-02-01
• Subjects: D. SiC -- Phase diagram -- Liquid phase sintering -- X-ray diffraction; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2015.10.064
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: SiC (containing) ceramics were fabricated by pressureless sintering or hot pressing using SiC, Al2 O3, Gd2 O3 and SiO2 as starting materials. Phase compositions of the ceramics were detected by X-ray diffraction (XRD). The results showed that SiC was compatible with Al2 O3, SiO2 and Gd2 O3 at <1700 °C. Six binary oxide compounds, i.e. Gd4 Al2 O9 (GdAM), GdAlO3 (GdAP), Gd2 SiO5, Gd2 Si2 O7, Gd9.33 (SiO4 )6 O2 (GdH) and mullite, and two solid solutions, i.e. Gd4 Al2(1− x ) Si2 x O9+ x (GdAMss) on the GdAM–Gd2 SiO5 tie-line and the Gd9.33+2 x (Si1− x Al x O4 )6 O2 (GdHss) on the Gd9.33 (SiO4 )6 O2 –GdAM tie-line formed. The GdAP phase was compatible with each of GdH, Al2 O3 and SiC, but was incompatible with Gd2 Si2 O7 or mullite. Based on this information, seven four-phase compatible regions were established in the subsolidus phase diagram of the Gd2 O3 –Al2 O3 –SiO2 –SiC quaternary system. Effects of the presence of SiO2 on liquid phase sintering and high-temperature strength of the SiC ceramics were clarified.