In:
Key Engineering Materials, Trans Tech Publications, Ltd., Vol. 697 ( 2016-7), p. 530-534
Abstract:
The Zr 2 Al 4 C 5 ceramic was successfully fabricated by the spark plasma sintering at 1800 °C for 10 min under uniaxial 20 MPa pressure in vacuum using a mixed raw materials of Zr, Al, Si and graphite powders. The X-ray diffraction analysis results showed that the unexpected Zr 2 Al 3 C 5 phase rather than target compound Zr 2 Al 4 C 5 formed in the sintered samples. An initial Zr:Al:C molar ratio of 2:4.2:4.8 for raw powders, and even 55 mol.% excess Al, did not lead to a phase transformation from Zr 2 Al 3 C 5 to Zr 2 Al 4 C 5 . When 4 wt.% Si was induced in the starting powders, the major phase became Zr 2 Al 4 C 5 and no obvious Zr 2 Al 3 C 5 was detected in the sintered samples with an initial Zr:Al:C molar ratio of 2:6.2:4.8 (55 mol.% excess Al). The introduction of Si could suppress and even remove additional ZrC, and Si atoms would exclusively occupy the site of Al to make Zr 2 Al 4 C 5 become a stable solid solution. The scanning electron microscopy observation showed that the as-synthesized Zr 2 Al 4 C 5 grains had elongated, rod-like and/or plate-like shapes. The mechanical properties of the sintered Zr 2 Al 4 C 5 ceramic were also investigated, and it showed a hardness of 11.06±0.34 GPa and a fracture toughness of 4.6 ± 0.4 MPa×m 1/2 .
Type of Medium:
Online Resource
ISSN:
1662-9795
DOI:
10.4028/www.scientific.net/KEM.697
DOI:
10.4028/www.scientific.net/KEM.697.530
Language:
Unknown
Publisher:
Trans Tech Publications, Ltd.
Publication Date:
2016
detail.hit.zdb_id:
2073306-9
