Metals parts containing a protective coating
AssigneeSolvay Fluor GmbH
InventorsPlacido Garcia-Juan, Ulrich Seseke-Koyro, Dagmar Bonhage
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Abstract
Metal parts, especially parts made from aluminium, aluminium alloys, steel and stainless steel, are described which comprise a coating containing TiOF2 or titanyl hydroxyfluorides. The coating protects against corrosion. Titanium oxyfluoride and titanyl hydroxyfluorides in the form of a gel are also disclosed, as well as particulate Ti0.85O0.55(OH)1.1F1.2 having a specific particle size.
Claims17
A metal part with improved protection against corrosion comprising a coating containing a titanium compound selected from the group consisting of titanyl oxyfluoride and titanyl hydroxyfluorides of general formula TiaOb(OH)cFd wherein a is 0.8 to 1.2;
- b is 0.5 to 1.7;
- c is 0.2 to 1.7;
- and d is 0.2 to 1.8.
Titanyl hydroxyfluoride, crystallized in the hexagonal tungsten bronze (HTB) form, of formula Ti0.85O0.55(OH)1.1F1.2 wherein the indices are variable in a range of ±0.03, with a primary particle size essentially in the range of 100 to 700 nm and a secondary particle size essentially in the range of 1 to 5 μm.
A suspension of Ti0.85O0.55(OH)1.1F1.2 in a mono- or dibasic alcohol, in a ketone, or in an ether.
A titanium compound in the form of a gel, selected from the group consisting of TiOF2 and TiaOb(OH)cFd wherein a is 0.8 to 1.2;
- b is 0.5 to 1.7;
- c is 0.2 to 1.7;
- and d is 0.2 to 1.8.
A process for the preparation of Ti0.85O0.55(OH)1.1F1.2 which crystallizes in the hexagonal tungsten bronze (HTB) structure wherein the indices are variable in a range of ±0.03, comprising providing a solution of titanyl chloride in hydrochloric acid, and adding hydrofluoric acid to the solution with the proviso that the molar ratio of HF to titanylchloride is equal or lower than 2.
A process for the preparation of a titanium compound in the form of a gel, selected from the group consisting of TiOF2 and TiaOb(OH)cFd wherein a is 0.8 to 1.2;
- b is 0.5 to 1.7;
- c is 0.2 to 1.7;
- and d is 0.2 to 1.8, said process comprising reacting a titanium tetraalkoxide with aqueous HF in an organic solvent.
Dependencies are inferred from the claim text.