Hydrothermal Reaction Sintering of Pure Cr₂O₃

Abstract

Much work has been done in an effort to fabricate a pure high-density Cr₂O₃. High volatilization of chromium oxide compounds, however, made its densification difficult. The studies reported to date on the sintering of Cr₂O₃ have been concerned mainly with controlling the sintering atmosphere and the additives. Hagel et al. ¹ studied the initial sintering of Cr₂O₃ in an Ar atmosphere with a ${p_{{{\text{O}}_{\text{2}}}}}$ of ≈10⁻² mm Hg but were unable to obtain a high density. Ownby and Jungquist² studied the final sintering of Cr₂O₃, giving attention to the effect of oxygen activity and the addition of MgO on the sintering of Cr₂O₃. At 1600°C, their product approached theoretical density at ${p_{{O_2}}} = 2 \times {10^{ - 12}}$ atm, whereas the high weight loss due to volatilization of chromium oxides was observed at ${p_{{O_2}}} < {10^{ - 12}}$ atm where the maximum density was achieved.