Oxidation mechanism of the Inconel 601 alloy at high temperatures

The Inconel 601 alloy oxidation was performed in air, in the temperature range 1000-1150 °C, during 90 h. Kinetic results show that the parabolic behavior is always followed in this temperature range. The Arrhenius plot of the kp values shows two different activation energies. Between 1000 and 1050 °C the activation energy is E a1 = 160 ± 10 kJ/mol. In the 1050-1150 °C temperature range a higher value is calculated E a2 = 252 ± 20 kJ/mol. The E a2 value and the X-ray diffraction (XRD) results and scanning electron microscope (SEM) energy dispersive X-ray spectroscopy (EDS) examinations are in accordance with a scale growth mechanism limited by a growing Cr 2 O 3 scale acting as a diffusion …

Bridgman growth of paratellurite single crystals

Abstract The growth of paratellurite single crystals by the vertical-gradient freezing technique is reported for the first time. Boules of 120 mm long and 25 mm in diameter were obtained under a temperature gradient of 10°C cm −1 and translation rates lower than 0.6 mm h −1 . The spatial distribution of defects along the growth axis reveals a continuous evolution of the free convective fluid-flow regime as growth proceeds. Gas bubbles and dark inclusions rejected to the periphery in the upper part of the crystal are observed to lay preferentially in (1 0 0), (0 0 1), ( 1 1 ¯ 0 ) and (1 1 2) crystallographic planes. Among them, SEM and microprobe analyses evidenced the presence of metallic p…

"Study of Niobium Aluminide synthesis using MASHS and M2AP processes"

Rôle joué par les dépôts sol gel de lanthane sur l’oxydation de l’alliage 330Cb (Fe-35Ni-18Cr-1Nb-2Si) à 900 °C

Cette etude a ete menee afin de tester l’influence d’un depot sol-gel de lanthane sur l’adherence des couches d’oxyde formees a 900 °C sur le 330Cb (Fe-35Ni-18Cr-1Nb-2Si). Le but de cette oxydation est de constituer une couche de chromine protectrice en vue d’ameliorer la resistance des tapis de fours vis-a-vis de la carburation. Une attention toute particuliere est portee sur le caractere protecteur du depot sol gel de lanthane en fonction de la temperature de son recuit prealable sous argon (entre 600 et 1000 °C).