Nomenclature
CAS number: 1344-28-1
Alumina.
Al
2O
3; mol wt 101.96.
Al 52.93%, O 47.08%.
Description and references
Occurs in nature as the minerals: bauxite, bayerite, boehmite, corundum, diaspore, gibbsite. Prepn and properties: Mellor's vol. V, 263-273 (1929); Gmelins,
Aluminum (8th ed.) 35B, pp 7-98 (1934); Becher
in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd
ed., 1963) pp 822-823; Wagner, ibid. vol. 2 (1965)
pp 1660-1663. Use as column matrix in ion chromatography: W. Buchberger,
K. Winsauer, J. Chromatogr. 482, 401 (1989); in HPLC: M. T. Kelly, M. R. Smyth, J. Pharm. Biomed. Anal. 7, 1757
(1989). Clinical evaluation in hip replacement: L. Sedel et
al., J. Bone Joint Surg. Br. 72-B, 658 (1990); of wear in hip replacement: L. P.
Zichner, H.-G. Willert, Clin. Orthop. Relat.
Res. 282, 86 (1992). Review of properties,
biocompatibility and clinical use: P. Boutin et al., J. Biomed. Mater. Res. 22, 1203-1232
(1988); of biocompatibility: P. S. Christel, Clin. Orthop. Relat. Res. 282, 10-18 (1992).
Properties
Approximate characteristics of native aluminum
oxide: White cryst powder. Very hard, about 8.8 on Moh's scale.
An electrical insulator; electrical resistivity at 300° about 1.2 ×
1013 ohms-cm. When heated above 800° it becomes insol in
acid and specific gravity increases from 2.8 to 4.0. Insol in water.
Very hygroscopic.Caution
Potential symptoms of overexposure
by direct contact are irritation of eyes, skin and respiratory system.
See NIOSH Pocket Guide to Chemical
Hazards (DHHS/NIOSH 97-140, 1997) p 12.Use
As adsorbent, desiccant, abrasive; as filler for
paints and varnishes; in manuf of alloys, ceramic materials, electrical
insulators and resistors, dental cements, glass, steel, artificial
gems; in coatings for metals, etc.; as catalyst for organic reactions.
As a chromotagraphic matrix; originally called
Brockmann aluminum oxide when used for this purpose. The minerals
corundum (hardness = 9) and
Alundum (obtained by fusing bauxite in an electric furnace) are
used as abrasives and polishes; in manuf of refractories.