The paper summarizes recent results of lab-scale experiments on the carbothermal reduction of TiO_2 and Cr_2O_3. In both reduction reactions, the carbon particles are consumed and the oxide particles are the precursors of the hard phase that is formed. In the case of the reduction of TiO_2 the experiments were focussed on the role of Ti_2O_3 as an oxide intermediate and on the investigation of the effect of nitrogen on the whole reaction mechanism. Due to its instability in nitrogen-containing atmospheres, Ti_2O_3 does not appear as an intermediate reaction product if nitrogen is present. Nitrogen is incorporated into the solid phase as cubic TiC_xO_yN_z is formed, its content depending on its partial pressure. Independent of the composition of the starting Cr_2O_3 ― C mixture in the reduction, Cr_3C_2 is the first carbide formed, hypothetically as a protective layer around the Cr_2O_3 particles.
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