The Vapor-phase Reaction of Aluminium Trichloride with Oxygen in the Presence of Steam and Properties of the Aluminium Oxide Formed

Abstract

The reaction of gaseous AlCl3 with oxygen containing 2–5 vol% H2O in the temperature range of 200 to 1000 °C, and the thermal transitions of the Al2O3 formed under various conditions were examined. At 200 °C, only the reaction of gaseous AlCl3 with H2O occurs, regardless of the H2O content in oxygen. Above about 400 °C, the reactions of gaseous AlCl3 with both H2O and oxygen occur, and all the AlCl3 reacts at 1000 °C. The reaction with H2O mainly occurs below about 900 °C, and the reaction with oxygen mainly occurs at 1000 °C. Regardless of the H2O content in oxygen, the reaction product is amorphous Al2O3 below 600 °C, amorphous Al2O3 containing poorly crystallized γ-Al2O3 at 800 °C, γ-Al2O3 containing amorphous Al2O3 at 900 °C, and a mixture of γ-Al2O3 and δ-Al2O3 at 1000 °C. It was also observed that the Al2O3 formed below 800 °C included a chloride oxide of aluminium. On heating the amorphous Al2O3 formed by the reaction of gaseous AlCl3 with oxygen containing 2–5 vol% H2O, the amorphous \xrightarrowca.700°Cχ\xrightarrowca.800°Cκ\xrightarrowca.1000°Cα transition occurs; on heating the γ-Al2O3 formed, the γ \xrightarrowca.900°Cδ \xrightarrowca.1000°Cθ \xrightarrowca.1000°Cα transition occurs.

X-ray diffraction and calorimetric studies of powder nanocrystalline systems based on ZrO2(Y) and Al2O3 with second insoluble component

“…Table 3 lists the estimated CSD phase sizes existing in the powders. It is seen that the CSD sizes of the γ and δ structures in the Al 2 O 3 powder are slightly larger [20]. It follows from the data that, in powder no.…”