EP 0328908 B1 19920304 - PROCESS FOR APPLYING CONVERSION COATINGS
Title (en)
PROCESS FOR APPLYING CONVERSION COATINGS
Publication
Application
Priority
GB 8802788 A 19880208
Abstract (en)
[origin: DE3902266A1] In a process for applying conversion coatings to metal surfaces of aluminium, zinc and their alloys with the aid of alkaline solutions containing chromium(VI) and chromium(III), the solution used contains at least 20 ppm, preferably from 100 to 500 ppm, of dissolved chromium(III) as a result of the addition of a complexing agent for chromium(III), in particular a hydroxycarboxylic acid and/or an aminocarboxylic acid. The chromium(III) is advantageously introduced as nitrate, sulphate, phosphate and/or acetate. The chromium(VI) content should be from 8 to 75 ppm, preferably from 15 to 60 ppm, and the pH of the solution should be at least 12, preferably at least 12.5.
IPC 1-7
IPC 8 full level
C23C 22/60 (2006.01); C23C 22/67 (2006.01)
CPC (source: EP US)
C23C 22/60 (2013.01 - EP US); C23C 22/67 (2013.01 - EP US)
Designated contracting state (EPC)
BE DE ES FR IT NL SE
DOCDB simple family (publication)
EP 0328908 A1 19890823; EP 0328908 B1 19920304; AU 2969189 A 19890810; AU 614024 B2 19910815; DE 3902266 A1 19890817; DE 58900881 D1 19920409; ES 2031288 T3 19921201; GB 8802788 D0 19880309; JP H01283386 A 19891114; NZ 227807 A 19910827; US 4963198 A 19901016
DOCDB simple family (application)
EP 89101302 A 19890126; AU 2969189 A 19890207; DE 3902266 A 19890126; DE 58900881 T 19890126; ES 89101302 T 19890126; GB 8802788 A 19880208; JP 2409489 A 19890203; NZ 22780789 A 19890131; US 30773089 A 19890207