High Temperature Oxidation of a Nanolayer Laminated (Cr<SUB>0.95</SUB>Ti<SUB>0.05</SUB>)<SUB>2</SUB> AlC Compound in Air

Abstract

High-purity, dense nano-laminated (Cr0.95Ti0.05)2AlC compounds were synthesized via a powder metallurgical route. Their oxidation characteristics were investigated by exposing them to temperatures between 900 and 1200 degrees C in air. The alloying Ti in the Cr layer of Cr2AlC did not significantly change the crystal structure and microstructure of Cr2AlC. But, it increased the oxidation rate of the Cr,AlC. The scale morphology of the (Cr0.95Ti0.05)2AlC was basically similar to that of the pure Cr2AlC. The main difference was that the (Cr0.95Ti0.05)2AlC contained oxide nodules. These formed because the titanium oxidized to TiO2, making the Cr2AlC susceptible to nodular oxidation. However, alpha-Al2O3 was still the major oxidation product in both the (Cr0.95Ti0.05)2AlC and pure Cr2AlC.

On the stochastic phase stability of Ti2AlC-Cr2AlC

“…This projects to the solubility of ~3 at.% Ti at 1300 °C which is slightly less than those of Lee et al . 23, 24 and Horlait et al . 20 which are ~5 at .% Ti.…”

“…22 and Lee et al . 23 both tried to synthesize (Cr,Ti) 2 AlC in 2010. In their work, the focus was on the Cr-rich side and they have concluded, based on X-ray diffraction analysis, that the maximum solubility of Ti in Cr 2 AlC is somewhere between 10 and 20 at .%, lower than that reported by Schuster et al .. Interestingly, Lee et al .…”

“…In their work, the focus was on the Cr-rich side and they have concluded, based on X-ray diffraction analysis, that the maximum solubility of Ti in Cr 2 AlC is somewhere between 10 and 20 at .%, lower than that reported by Schuster et al .. Interestingly, Lee et al . 23, 24 , while studying (Cr 0.95 Ti 0.05 ) 2 AlC, have pointed out that the solubility of Ti in Cr 2 AlC is limited to only 5 at .%, raising an interesting fundamental question on the maximum solubility of Ti in Cr 2 AlC. To follow, Ying et al .…”

Comparison of microstructure and chemical durability of Ce0.9Gd0.1PO4 ceramics prepared by hot-press and pressureless sintering

“…These monazite ceramic waste-forms were generally sintered by the conventional pressureless sintering (PLS) process, the sintering temperature is relatively high (1300-1450 1C) and holding time is relatively long (4-10 h). However, the hot-press sintering (HPS) offers several advantages over conventional methods, primarily the very low-temperature required for densification [34][35][36]. Teng et al [35] prepared Ce IV -doped titanate ceramics with relative densities over 99% by HPS at temperature as low as 1150 1C for 1-4 h and under the pressure of 30 MPa.…”

Effect of sintering technique on mechanical property and chemical durability of Ce0.5Pr0.5PO4 ceramics

“…A series of monazite-type CePO 4 doped with Pr, Eu and Gd solid solutions were successfully prepared by the solid state method [22,27,28]. Compared with NPS, the hot-pressing (HPS) process is viewed as a low-temperature and rapid densification technique [36][37][38]. Arinicheva et al [39] have reported (La, Eu)PO 4 monazite ceramics with relative density in excess of 98% by uniaxial HPS at a sintering temperature of 1350 ºC and under the pressure of 50 MPa.…”