	US 11,686,000 B2
	Composition and method for the chromium-free pretreatment of aluminium surfaces
Heiko Hellmers, Frankfurt am Main (DE); Thomas Wendel, Frankfurt am Main (DE); and Norbert Maurus, Frankfurt am Main (DE)
Assigned to CHEMETALL GMBH, Frankfurt (DE)
Appl. No. 16/463,196
Filed by Chemetall GmbH, Frankfurt (DE)
PCT Filed Oct. 25, 2017, PCT No. PCT/EP2017/077308 § 371(c)(1), (2) Date May 22, 2019, PCT Pub. No. WO2018/095684, PCT Pub. Date May 31, 2018.
Claims priority of application No. 102016223170.7 (DE), filed on Nov. 23, 2016.
Prior Publication US 2020/0063267 A1, Feb. 27, 2020
Int. Cl. C23C 22/44 (2006.01); C23C 22/36 (2006.01); C22C 21/00 (2006.01)

CPC C23C 22/44 (2013.01) [C23C 22/361 (2013.01); C22C 21/00 (2013.01)]

20 Claims

1. An aqueous, chromium-free composition for a pretreatment of aluminum surfaces, which comprises at least one water-soluble phosphorus compound, at least one water-soluble zirconium compound, at least one water-soluble titanium compound, and at least one water-soluble molybdenum compound, a phosphorus compound content being in a range from 25 to 40 mg/l calculated as phosphorus, a zirconium compound content being in a range from 400 to 600 mg/l calculated as metal, a titanium compound content being in a range from 200 to 400 mg/l calculated as metal, and a molybdenum compound content being in a range from 40 to 150 mg/l calculated as metal, the aqueous composition having a pH at room temperature in a range from 2.0 to 5.0.