Silver coated mirror

• US 20010033935A1
• Filed: 04/17/2001
• Published: 10/25/2001
• Est. Priority Date: 05/12/1994
• Status: Active Grant

• Current Assignee: Glaverbel
• Original Assignee: Glaverbel
• Inventors: Boulanger, Pierre, Laroche, Pierre, Dauby, Christian
• Granted Patent: US 6,565,217 B2
• Time in Patent Office: Days
• US Class Current: 428/432
• CPC Class Codes: C03C 17/38 at least one coating being a coating of an organic material
• CPC Class Codes: C23C 18/1889 with use of metal first
• CPC Class Codes: G02B 5/0808 having a single reflecting layer G02B5/0883, G02B5/0891 take precedence

Abstract

A process for forming a silver coating on a surface of a vitreous substrate is described. The process comprises an activating step in which said surface is contacted with an activating solution, a sensitising step in which said surface is contacted with a sensitising solution, and a subsequent silvering step in which said surface is contacted with a silvering solution comprising a source of silver to form the silver coating. The process is characterised in that said activating solution comprises ions of at least one of bismuth (III), chromium (II), gold (III), indium (III), nickel (II), palladium (II), platinum (II), rhodium (III), ruthenium (III), titanium (III), vanadium (III) and zinc (II).

Claims

1. A process for forming a silver coating on a surface of a vitreous substrate, comprising an activating step in which said surface is contacted with an activating solution, a sensitising step in which said surface is contacted with a sensitising solution, and a subsequent silvering step in which said surface is contacted with a silvering solution comprising a source of silver to form the silver coating, wherein said activating solution comprises ions of at least one of bismuth (III), chromium (II), gold (III), indium (III), nickel (II), palladium (II), platinum (II), rhodium (III), ruthenium (III), titanium (III), vanadium (III) and zinc (II).

2. The process according to

claim 1

, wherein, in said sensitising step said surface is contacted with a sensitising solution comprising tin (II) chloride.

3. The process according to

claim 1

, wherein said sensitising step is carried out prior to said activating step.

4. The process according to

claim 1

, wherein said substrate is a flat sheet of glass.

5. The process according to

claim 1

, wherein the thickness of the layer of silver formed in said silvering step is between 8 nm and 30 nm.

6. The process according to

claim 1

, wherein the thickness of the layer of silver formed in said silvering step is between 70 nm and 100 nm.

7. The process according to

claim 1

, wherein said activating solution is an aqueous solution of palladium chloride.

8. The process according to

claim 7

, wherein said palladium chloride solution has a concentration of from 5 to 130 mg/l.

9. The process according to

claim 7

, wherein the glass is contacted with 1 to 23 mg PdCl₂ per square meter of said substrate surface.

10. The process according to

claim 7

, wherein the glass is contacted with at least 5 mg PdCl₂ per square meter of said substrate surface.

11. The process according to

claim 1

, wherein the pH of said activating solution is from 3.0 to 5.0.

12. The process according to

claim 1

, wherein the silver coating is subsequently contacted with a solution containing ions of at least one of the group consisting of Cr (II), V (II or III), Ti (II or III), Fe (II), In (I or II), Sn (II), Cu (I) and Al (III).

13. A vitreous substrate having a silver coating formed on a surface thereof by a process according to

claim 1

.

14. A mirror comprising a vitreous substrate carrying a silver coating which is not covered with a protective layer of copper, the mirror exhibiting an average number of white specks of less than 10 per dm², after having been subjected to the accelerated ageing CASS Test and/or the Salt Fog Test defined herein.

15. The mirror according to

claim 14

, exhibiting an average number of white specks of less than 5 per dm², after having been subjected to the accelerated ageing CASS Test and/or the Salt Fog Test defined herein.