EP 3755825 A1 20201230 - PROCESS FOR SELECTIVE PHOSPHATING OF A COMPOSITE METAL CONSTRUCTION
Title (en)
PROCESS FOR SELECTIVE PHOSPHATING OF A COMPOSITE METAL CONSTRUCTION
Title (de)
VERFAHREN ZUR SELEKTIVEN PHOSPHATIERUNG EINER VERBUNDMETALLKONSTRUKTION
Title (fr)
PROCÉDÉ DE PHOSPHATATION SÉLECTIVE D'UNE CONSTRUCTION MÉTALLIQUE COMPOSITE
Publication
Application
Priority
- EP 18157294 A 20180219
- EP 2019053391 W 20190212
Abstract (en)
[origin: WO2019158508A1] The present invention relates to a process for chemical pretreatment and selective phosphating of a composite metal construction containing at least one part made of aluminium and at least one part made of zinc and optionally a further part made of iron which comprises (I) in a first step the treatment of the composite metal construction with an aqueous zinc phosphating composition which effects on the parts made of zinc and iron the formation of a surface-covering crystalline zinc phosphate layer having a coating weight in the range from 0.5 to 5g/m2 but does not produce a zinc phosphate layer having a coating weight of at least 0.5g/m2 on the aluminium parts and subsequently - with an intermediate water washing cycle - comprises (II) in a second step the application of an aqueous acidic passivating composition having a pH in the range from 2.0 to 5.5 on the composite metal construction, wherein the acidic passivating composition removes from the parts made of zinc and iron not more than 50% of the crystalline zinc phosphate but forms a passive layer, which is not a surface-covering crystalline phosphate layer, on the aluminium parts, wherein the zinc phosphating composition in step (I) contains a content of sodium and/or potassium ions and of aluminium ions, wherein the zinc phosphating composition in step (I) has a temperature in the range from 20°C to 65°C and contains a content of free fluoride which is at least 5 mg/l but is not more than 200 mg/l, wherein the zinc phosphating composition contains at least 0.04 g/l but not more than 3.2 g/l of boron in the form of water-soluble inorganic compounds calculated as BF4 and wherein the pointage of the free acid with added KCl in the zinc phosphating composition is at least 0.6 points. The present invention further relates to a corresponding zinc phosphating composition, to a concentrate for the production thereof, to a corresponding composite metal construction and to the use thereof.
IPC 8 full level
C23C 22/73 (2006.01); C23C 22/34 (2006.01); C23C 22/36 (2006.01); C23C 22/40 (2006.01); C23C 22/44 (2006.01); C23C 22/80 (2006.01); C23C 22/83 (2006.01)
CPC (source: EP KR US)
C23C 22/34 (2013.01 - EP); C23C 22/362 (2013.01 - EP KR); C23C 22/364 (2013.01 - EP KR); C23C 22/365 (2013.01 - EP KR US); C23C 22/40 (2013.01 - EP); C23C 22/44 (2013.01 - EP); C23C 22/73 (2013.01 - EP KR US); C23C 22/80 (2013.01 - EP KR US); C23C 22/83 (2013.01 - EP KR US); C23C 22/44 (2013.01 - US); C23C 2222/20 (2013.01 - EP KR US)
Designated contracting state (EPC)
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated extension state (EPC)
BA ME
DOCDB simple family (publication)
WO 2019158508 A1 20190822; BR 112020015010 A2 20210119; CN 111742079 A 20201002; EP 3755825 A1 20201230; JP 2021515108 A 20210617; JP 2024026135 A 20240228; JP 7443253 B2 20240305; KR 20200121310 A 20201023; MX 2020008651 A 20200922; RU 2020130225 A 20220328; US 2021062346 A1 20210304
DOCDB simple family (application)
EP 2019053391 W 20190212; BR 112020015010 A 20190212; CN 201980013168 A 20190212; EP 19703128 A 20190212; JP 2020566876 A 20190212; JP 2023197516 A 20231121; KR 20207023528 A 20190212; MX 2020008651 A 20190212; RU 2020130225 A 20190212; US 201916964861 A 20190212