Claims
- 1. A method of making a multilayer pigment exclusively by a wet-chemical coating of a metal substrate in a one-pot process, comprising suspending the metal substrate in water at a pH 6-11 and coating with an amorphous glassy layer at a pH 6-11, and then coating with one or more metal oxides or metal oxide mixtures at a pH <4.
- 2. A method according to claim 1, wherein the amorphous glassy layer is created by precipitating SiQ2 from a sodium or a potassium silicate solution or by a hydrolytic decomposition of aluminum, tin, zinc, or boron salt.
- 3. A method according to claim 1, further comprising reducing the pH with a mineral acid after coating with an amorphous layer.
- 4. A method according to claim 3, further comprising adding one or more hydrolysable metal salts to precipitate at least one metal oxide or metal oxyhydrate directly onto the amorphous glassy layer without secondary precipitations.
- 5. A method according to claim 4, further comprising separating, washing, and drying an amorphous glassy coated pigment.
- 6. A method according to claim 5, wherein the metal substrate comprises aluminum or an alloy thereof, and the amorphous layer comprises SiO2.
Priority Claims (1)
Number |
Date |
Country |
Kind |
198 36 810 |
Aug 1998 |
DE |
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation application of U.S. patent application No. 09/762,766 filed Feb. 13, 2001 now abandoned, which is International Application No. PCT/EP99/05915, not published under PCT Article 21(2) in English.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
5441564 |
Vogt |
Aug 1995 |
A |
5607504 |
Schmid et al. |
Mar 1997 |
A |
5624486 |
Schmid et al. |
Apr 1997 |
A |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/762766 |
|
US |
Child |
10/453479 |
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US |