C-diffusion during hot press in the Al2O3-Cr2O3 system

Abstract Alumina is an important technological material due to its excellent physical and thermomechanical properties. Binary compositions enhance some of these properties; especially Cr additions significantly increase the mechanical behaviour of pure alumina. It is well known that the sintered bodies of chromium oxide doped-alumina do not become dense when sintering in air because vaporisation and condensation of Cr 2 O 3 during the high temperature densification process. The aim of this work is to assess the hot press sintering as an adequate processing method to obtain full dense sintered bodies from well homogeneous powders on chromia-alumina system. Using solutions of the desired nitrates, powders were prepared by the Pechini process in the range 0–6 Cr 2 O 3 wt% and hot-pressed at 1500 C. C-diffusion and microstructure of the final densed bodies were studied in order to evaluate synthesis process feasibility.