Investigation of Hot-Pressed Al2O3-Cr2O3/ Cr3C2 Nanocomposite

Abstract

Nanoscaled Cr2O3 powders coated on alumina particles have been produced by means of metal organic chemical vapor deposition (MOCVD) in a fluidized bed, using the pyrolysis of Cr(CO)6 precursor. In order to prepare the nanoscaled Cr3C2 powder from the Cr2O3, carbonizing behavior of the Cr2O3 particles was investigated. The carbon is from the decomposition of Cr(CO)6. It was found that Cr2O3 transformed into Cr3C2 at 1150 oC in graphite furnace in a vacuum level of 10-4 torr, while it could not carbonize at 1150oC in a vacuum level of 100 torr. In the present study, two reactions for Cr2O3 are carried out. One is that Cr2O3 reacts with Al2O3 to form a solid solution; the other is that Cr2O3 reacts with carbon to transform into chromium carbide. Consequently, a nanocomposite comprising the matrix of solid solution of Al2O3 - Cr2O3 and second phase Cr3C2 was prepared after hot-pressed.