Abnormal Grain Growth of Alumina: CaO Effect

Autor:	Sunggi Baik, Joonchul Jung
Rok vydání:	2003
Předmět:	Materials science Aluminate technology industry and agriculture Analytical chemistry Sintering Mineralogy Abnormal grain growth Intergranular corrosion Grain size chemistry.chemical_compound Grain growth chemistry Materials Chemistry Ceramics and Composites Grain boundary Calcium oxide
Zdroj:	Journal of the American Ceramic Society. 86:644-49
ISSN:	1551-2916 0002-7820
DOI:	10.1111/j.1151-2916.2003.tb03353.x
Popis:	The critical concentration of Ca required for the onset of abnormal grain growth in alumina was determined by controlled doping of Ca in ultrapure alumina (>99.999%), by sintering under clean contamination-free conditions, and by microstructural characterization. As in the case of Si, the excess concentration of Ca beyond its solubility limit was inversely related to the average grain size at the moment of first appearance of abnormal grains, which corresponds to the moment of sufficient enrichment of Ca in grain boundaries to form stable intergranular liquid films. However, the critical concentration of Ca was found to be in the range of only a few tens of ppm, which is lower than that of Si by almost 2 orders of magnitude. The equivalent silica concentration to form such a stable intergranular calcium aluminate glass film and its minimum thickness were estimated from the inverse relationship with the assumption that the glass composition is close to calcium hexaluminate.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::fdbd53c312f5e889d097b39c94d89a9f https://doi.org/10.1111/j.1151-2916.2003.tb03353.x Zobrazit plný text záznamu