Citation

Chuang SC, Kuo CT, Lee CS, Ho CT, Li AK. Journal of Materials Science 1992; 27(21): 5844-5848.

Copyright

(Copyright © 1992)

DOI

10.1007/BF01119748

PMID

unavailable

Abstract

In situ formation of chromium carbide particles, through a solid state reaction between Cr2O3 and SiC, for strengthening AI2O3 has been studied. Three kinds of chromium compound, Cr3Si, Cr3C2 and Cr7C3 and mullite were formed in the alumina matrix. The reaction behaviour during hot pressing depends on heating parameters such as temperature and atmosphere. In a vacuum environment, the Cr3Si particles formed first and was the dominant dispersed phase below 1550°C, while the Cr7C3 phase was only dominant above 1600°C. The Cr3C2 phase emerged briefly then diminished at temperature ≥ 1500°C. In an argon environment, however, the Cr3C2 phase was the main product component at temperatures ranging from 1450-1550 °C. The mullite phase formed concurrently through the diffusion of SiO2 phase into the Al2O3 matrix, which is a by-product from the reaction between Cr2O3 and SiC. Incorporating chromium carbide or suicide particles into the Al2O3 matrix induces a strengthening effect. However, only when the content of dispersed phases is low and is mainly of Cr3C2 particles, is the strengthening effect significant. For instance, the composite, containing 5 vol% chromium carbide and hot-pressed at 1500°C in argon, gives a flexural strength and fracture toughness up to 600 MPa and 6.1 MPam1/2, respectively. © 1992 Chapman & Hall.

Language: en