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Oxidation of a Silicon Nitride‐Titanium Nitride Composite: Microstructural Investigations and Phenomenological Modeling

2002; Wiley; Volume: 85; Issue: 7 Linguagem: Inglês

10.1111/j.1151-2916.2002.tb00365.x

1551-2916

Frédéric Deschaux‐Beaume, Thierry Cutard, Nicole Fréty, Christophe Levaillant,

MXene and MAX Phase Materials

The high‐temperature oxidation of a silicon nitride‐titanium nitride (Si 3 N 4 –TiN) composite has been investigated via scanning electron microscopy and energy‐dispersive and wavelength‐dispersive spectrometry. At 1150°C, the oxidation of both the silicon nitride and titanium nitride phases takes place. Several oxidation processes act simultaneously and/or successively. First, the oxidation of the titanium nitride occurs and leads to the formation of a continuous titanium oxide (TiO 2 ) crystal layer at the surface. Next, the TiO 2 formation takes place in the sublayer at the same time as the Si 3 N 4 oxidation. The oxidation of this last phase leads to the formation of vitreous silica (SiO 2 ). For long a duration of oxidation (>50 h), a continuous layer of SiO 2 is formed under the outer TiO 2 scale. Large pores grow in this layer and deform the outer oxide layers, whereas the oxidation occurs in the material. Based on these results and bibliographical data, a phenomenological model is proposed to describe the stages of the high‐temperature oxidation of Si 3 N 4 –TiN materials.