Segregation of Si and Ti in α-alumina

• Published in: Materials letters Vol. 41; no. 4; pp. 198 - 203
• Main Authors: Kebbede, Anteneh, Carim, Altaf H
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.11.1999; Elsevier
• Subjects: Alumina; Anisotropic; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; EDS; Exact sciences and technology; Impurities: concentration, distribution, and gradients; Impurity concentration, distribution, and gradients; Physics; Segregation; Silicon; Structure of solids and liquids; crystallography; Titania; Anisotropic; Silicon; Titania; Segregation; EDS; Alumina; Spectroscopy; Inorganic compounds; Binary compounds; Experimental study; Silicon additions; Titanium additions; Oxide ceramics; Energy dispersion; Impurities; Anisotropy; Microstructure; Impurity segregation; TEM; Codoping; Aluminium oxides
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/S0167-577X(99)00130-5

The segregation of Si and Ti in 0.6 wt.% TiO 2-doped α-Al 2O 3 containing ∼0.05 wt.% impurity Si was characterized. The material developed an anisotropic microstructure consisting of alumina platelets in an equiaxed matrix. Si collects to form an amorphous aluminosilicate layer at basal boundaries of platelets, but little Si is present at any other grain boundaries. Ti segregates preferentially to the faceted or curved edge boundaries of platelets, with a concentration there that is nearly three times as high as at basal surfaces. Ti segregation to boundaries between equiaxed grains was intermediate and showed no significant or systematic boundary-to-boundary variation.