(19)

(11)

EP 0 964 939 A1

(12)

(43) Date of publication: 22.12.1999 Bulletin 1999/51 (21) Application number: 97927591.0 (22) Date of filing: 07.03.1997

(51) International Patent Classification (IPC):  C22C 21/ 16( . ) C22F 1/ 057( . ) (86) International application number: PCT/US1997/003638 (87) International publication number: WO 1998/039494 (11.09.1998 Gazette 1998/36)

(84) Designated Contracting States: DE ES FR GB IT NL (71) Applicant: ALUMINUM COMPANY OF AMERICA Alcoa Center, Pennsylvania 15069-0001 (US)	(72) Inventor: KARABIN, Lynnette, M., Alcoa Technical Center Alcoa Center, PA 15069-0001 (US) (74) Representative: Baillie, Iain Cameron  Ladas & Parry, Dachauerstrasse 37 80335 München 80335 München (DE)