Global Patent Index - EP 0399169 A3

EP 0399169 A3 19910123 - CHEMICAL PROCESS TO AVOID A RAINBOW EFFECT, PROVOKED BY AN OXIDE LAYER THAT IS CAUSED DURING THE POLISHING OF PIECES OF ALUMINIUM OR PIECES OF ALUMINIUM ALLOYS

Title (en)

CHEMICAL PROCESS TO AVOID A RAINBOW EFFECT, PROVOKED BY AN OXIDE LAYER THAT IS CAUSED DURING THE POLISHING OF PIECES OF ALUMINIUM OR PIECES OF ALUMINIUM ALLOYS

Publication

EP 0399169 A3 19910123 (DE)

Application

EP 90105558 A 19900323

Priority

DE 3917186 A 19890526

Abstract (en)

[origin: EP0399169A2] A description is given of a chemical process for avoiding a rainbow effect provoked by the oxide layer produced during the polishing of aluminium or aluminium-alloy parts. In the process, the parts are degreased or cleaned in a first process step and given an electrolytic alkaline polish in a second process step. The process is distinguished by the fact that, after polishing, the pieces are subjected to a further treatment in which they are first rinsed in water, then exposed to a chromic acid solution containing about 50 g/l of CrO3 at about 98 DEG C for about three minutes, and finally rinsed in a sodium hydrogensulphite solution.

IPC 1-7

C25F 3/20

IPC 8 full level

C25D 11/24 (2006.01); C25F 3/20 (2006.01)

CPC (source: EP US)

C25F 3/20 (2013.01 - EP US)

Citation (search report)

Designated contracting state (EPC)

BE DE ES FR GB IT SE

DOCDB simple family (publication)

EP 0399169 A2 19901128; EP 0399169 A3 19910123; EP 0399169 B1 19930811; DE 3917186 A1 19901129; DE 3917186 C2 19920625; DE 59002260 D1 19930916; JP H0313598 A 19910122; JP H0579759 B2 19931104; US 5009756 A 19910423

DOCDB simple family (application)

EP 90105558 A 19900323; DE 3917186 A 19890526; DE 59002260 T 19900323; JP 13554190 A 19900528; US 52758790 A 19900523