(19)

(11)

EP 0 370 075 A1

(12)

(43) Date of publication: 30.05.1990 Bulletin 1990/22 (21) Application number: 89901180.0 (22) Date of filing: 19.12.1988

(51) International Patent Classification (IPC):  C22B 21/ 00( . ) C25C 3/ 02( . ) C25C 3/ 06( . ) C25C 7/ 02( . ) C25C 3/ 00( . ) C25C 3/ 04( . ) C25C 3/ 12( . ) (86) International application number: PCT/US1988/004565 (87) International publication number: WO 1989/006289 (13.07.1989 Gazette 1989/15)

(84) Designated Contracting States: CH DE FR LI (30) Priority: 28.12.1987 US 19870138391 24.05.1988 US 19880197889 (71) Applicant: ALUMINUM COMPANY OF AMERICA Pittsburgh, PA 15219 (US)	(72) Inventors: LaCAMERA, Alfred, F. Trafford, PA 15086 (US) VAN LINDEN, Jan, H., L. Allison Park, PA 15101 (US) PIERCE, Thomas, V. Delmont, PA 15626 (US) PARKHILL, James, O. Tarentum, PA 15084 (US) (74) Representative: Baillie, Iain Cameron, et al  c/o Ladas & Parry Altheimer Eck 2 D-80331 München D-80331 München (DE)