The influence of surface structure on wetting of α-Al 2O 3 by aluminum in a reduced atmosphere

• Published in: Acta materialia Vol. 51; no. 16; pp. 4897 - 4906
• Main Authors: Shen, Ping, Fujii, Hidetoshi, Matsumoto, Taihei, Nogi, Kiyoshi
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2003
• Subjects: Crystallographic orientation; Surface; Wetting; Wetting; Crystallographic orientation; Al; Surface
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(03)00332-X

An improved sessile-drop wetting experiment was performed in this study to investigate the wettability and adhesion of molten Al on three different oriented α-Al 2O 3 single crystals, R ( 01 1 2 ), A (11 2 0 ) and C(0001), over a wide temperature range from 800–1500 °C in a reduced Ar-3%H 2 atmosphere. It is found that the wettability and adhesion between molten Al and α-Al 2O 3 are quite sensitive to the crystallographic orientation. The adhesion is much stronger for the molten Al on the R and A surfaces than that on the C surface. On the other hand, the adhesion on the reconstructed C- ( 31 × 31 )R±9 ∘ surface is weaker than that on the relaxed yet unreconstructed C-(1×1) surface. The results suggest that in the reduced Ar-3%H 2 atmosphere, the top layers of the R and A α-Al 2O 3 surfaces are oxygen-terminated while that of the C surface is aluminum-terminated, and the reconstructed C- ( 31 × 31 )R±9 o surface is an oxygen-deficient structure based on the results of the work of adhesion.