Effect of Temperature and Oxygen Partial Pressure on the Oxidation of Titanium Carbide

Abstract

Two capsules, identical except that only one was sealed, were held at 1550'C for 9 hr. The weight change in the sealed capsule, relative to the charge, was less than 1%; the loss in the open capsule was 6%.The sealed capsules were always puffed or swollen after the experiment, even when the capsules had been heated to above 800°C for 24 hr and had been sealed while hot. In fact, i t was not possible to obtain satisfactory runs above 1550'C because of rupture of the sealed platinum capsules. It is thus probable that the vapor pressure in the dry system above 1550°C is considerably higher than 1 bar and possibly higher than 10 bars.

The effect of the TiC particle size on the preferred oxidation temperature for self-healing of oxide ceramic matrix materials

“…The activation energies determined here are comparable to those determined in other studies (e.g. [11,25]), i.e. 192 and 245 kJ mol -1 .…”

“…the pre-exponential factor (A), can be evaluated from Eq. (11), once the reaction model is determined; cf. ''Reaction model'' section.…”

“…The oxidation behaviour of bulk TiC has already been investigated as a function of temperature (from 600 to 1200°C) and oxygen partial pressure (13-100 kPa) [10,11]. The observable trend in these studies is that oxidation proceeds parabolically from 600 to 800°C and switches to linear kinetics at higher temperatures and higher oxygen partial pressures.…”

“Ridge effect” in oxidation kinetics of hetero-modulus ceramics based on titanium carbide

“…Indeed, within this range, there is a clearly defined maximum weight gain, which corresponds to particular values of the oxidation parameters, but this maximum does not appear at the maximal temperature or oxygen pressure. Previously, Stewart and Cutler [12] have reported a maximum in the oxidation rates for TiC; Voitovich and Pugach [13] found the highest values of the rate at 800ºC, when studying oxidation of TiC at 600-1000ºC. Shimada and Kozeki [14] and Gozzi et al [15] reported about decrease in the oxidation rate with growing oxygen pressure.…”

“…The formation of carbon-doped anatase phase TiO 2-d C d with d = 0.02-0.05, as an initial product of TiC oxidation, was confirmed recently by Irie et al [20] as well as Shen et al [21] at lower temperatures in oxygen and air. There is available data in the literature on the activation energy for the parabolic oxidation of single crystals and polycrystalline TiC by oxygen [12,22] with values close to 200 kJ/mole; e.g. Voitovich and Lavrenko [30] determined the value of Q in the interval from 184 to 217.5 kJ/mole, to be dependent on the purity of the TiC phase.…”